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https://github.com/stdlib-js/array-bool

BooleanArray.
https://github.com/stdlib-js/array-bool

array binary bool boolean booleanarray data javascript mask node node-js nodejs stdlib structure typed typed-array types

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BooleanArray.

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README 

        



  

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# BooleanArray



[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] 



> Boolean array.



## Installation



```bash

npm install @stdlib/array-bool

```



Alternatively,



-   To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).

-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).

-   For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).



The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.



To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.



## Usage



```javascript

var BooleanArray = require( '@stdlib/array-bool' );

```






#### BooleanArray()



Creates a boolean array.



```javascript

var arr = new BooleanArray();

// returns 

```



#### BooleanArray( length )



Creates a boolean array having a specified `length`.



```javascript

var arr = new BooleanArray( 10 );

// returns 



var len = arr.length;

// returns 10

```



#### BooleanArray( booleanarray )



Creates a boolean array from another boolean array.



```javascript

var arr1 = new BooleanArray( [ true, false, false, true ] );

// returns 



var arr2 = new BooleanArray( arr1 );

// returns 



var len = arr2.length;

// returns 4

```



#### BooleanArray( typedarray )



Creates a boolean array from a [typed array][@stdlib/array/typed].



```javascript

var Uint8Array = require( '@stdlib/array-uint8' );



var buf = new Uint8Array( [ 1, 0, 0, 1 ] );

// returns [ 1, 0, 0, 1 ]



var arr = new BooleanArray( buf );

// returns 



var len = arr.length;

// returns 4

```



#### BooleanArray( obj )



Creates a boolean array from an array-like object or iterable.



```javascript

// From an array of booleans:

var arr1 = new BooleanArray( [ true, false, false, true ] );

// returns 



var len = arr1.length;

// returns 4



// From an array containing non-booleans:

var arr2 = new BooleanArray( [ {}, null, '', 4 ] );



len = arr2.length;

// returns 4

```



#### BooleanArray( buffer\[, byteOffset\[, length]] )



Returns a boolean array view of an [`ArrayBuffer`][@stdlib/array/buffer].



```javascript

var ArrayBuffer = require( '@stdlib/array-buffer' );

var buf = new ArrayBuffer( 240 );



var arr1 = new BooleanArray( buf );

// returns 



var len = arr1.length;

// returns 240



var arr2 = new BooleanArray( buf, 8 );

// returns 



len = arr2.length;

// returns 232



var arr3 = new BooleanArray( buf, 8, 20 );

// returns 



len = arr3.length;

// returns 20

```



* * *



### Properties






#### BooleanArray.BYTES_PER_ELEMENT



Static property returning the size (in bytes) of each array element.



```javascript

var nbytes = BooleanArray.BYTES_PER_ELEMENT;

// returns 1

```






#### BooleanArray.name



Static property returning the constructor name.



```javascript

var str = BooleanArray.name;

// returns 'BooleanArray'

```






#### BooleanArray.prototype.buffer



Pointer to the underlying data buffer.



```javascript

var arr = new BooleanArray( 2 );

// returns 



var buf = arr.buffer;

// returns 

```






#### BooleanArray.prototype.byteLength



Size (in bytes) of the array.



```javascript

var arr = new BooleanArray( 10 );

// returns 



var nbytes = arr.byteLength;

// returns 10

```






#### BooleanArray.prototype.byteOffset



Offset (in bytes) of the array from the start of its underlying `ArrayBuffer`.



```javascript

var ArrayBuffer = require( '@stdlib/array-buffer' );



var arr = new BooleanArray( 10 );

// returns 



var offset = arr.byteOffset;

// returns 0



var buf = new ArrayBuffer( 240 );

arr = new BooleanArray( buf, 64 );

// returns 



offset = arr.byteOffset;

// returns 64

```






#### BooleanArray.prototype.BYTES_PER_ELEMENT



Size (in bytes) of each array element.



```javascript

var arr = new BooleanArray( 10 );

// returns 



var nbytes = arr.BYTES_PER_ELEMENT;

// returns 1

```






#### BooleanArray.prototype.length



Number of array elements.



```javascript

var arr = new BooleanArray( 10 );

// returns 



var len = arr.length;

// returns 10

```



* * *



### Methods






#### BooleanArray.from( src\[, clbk\[, thisArg]] )



Creates a new boolean array from an array-like object or an iterable.



```javascript

var arr = BooleanArray.from( [ true, false ] );

// returns 



var len = arr.length;

// returns 2

```



To invoke a function for each `src` value, provide a callback function.



```javascript

function map( v ) {

    return !v;

}



// Create a source array:

var src = [ true, false ];



// Create a new boolean array by inverting the source array:

var arr = BooleanArray.from( src, map );

// returns 



var len = arr.length;

// returns 2



var v = arr.get( 0 );

// returns false



v = arr.get( 1 );

// returns true

```



A callback function is provided two arguments:



-   **value**: source value.

-   **index**: source index.



To set the callback execution context, provide a `thisArg`.



```javascript

function map( v ) {

    this.count += 1;

    return !v;

}



// Create a source array:

var src = [ true, false ];



// Define an execution context:

var ctx = {

    'count': 0

};



// Create a new boolean array by inverting the source array:

var arr = BooleanArray.from( src, map, ctx );

// returns 



var len = arr.length;

// returns 2



var n = ctx.count;

// returns 2

```






#### BooleanArray.of( element0\[, element1\[, ...elementN]] )



Creates a new boolean array from a variable number of arguments.



```javascript

var arr = BooleanArray.of( true, false, false, true );

// returns 



var len = arr.length;

// returns 4

```






#### BooleanArray.prototype.at( i )



Returns an array element located at integer position (index) `i`, with support for both nonnegative and negative integer positions.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var v = arr.at( 0 );

// returns true



v = arr.at( -1 );

// returns true

```



If provided an out-of-bounds index, the method returns `undefined`.



```javascript

var arr = new BooleanArray( 10 );



var v = arr.at( 100 );

// returns undefined



v = arr.at( -100 );

// returns undefined

```






#### BooleanArray.prototype.copyWithin( target, start\[, end] )



Copies a sequence of elements within the array starting at `start` and ending at `end` (non-inclusive) to the position starting at `target`.



```javascript

var arr = new BooleanArray( 4 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );

arr.set( true, 3 );



var v = arr.get( 0 );

// returns true



v = arr.get( 1 );

// returns false



// Copy the last two elements to the first two elements:

arr.copyWithin( 0, 2 );



v = arr.get( 0 );

// returns false



v = arr.get( 1 );

// returns true

```



By default, `end` equals the number of array elements (i.e., one more than the last array index). To limit the sequence length, provide an `end` argument.



```javascript

var arr = new BooleanArray( 4 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );

arr.set( true, 3 );



var v = arr.get( 2 );

// returns false



v = arr.get( 3 );

// returns true



// Copy the first two elements to the last two elements:

arr.copyWithin( 2, 0, 2 );



v = arr.get( 2 );

// returns true



v = arr.get( 3 );

// returns false

```



When a `target`, `start`, and/or `end` index is negative, the respective index is determined relative to the last array element. The following example achieves the same behavior as the previous example:



```javascript

var arr = new BooleanArray( 4 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );

arr.set( true, 3 );



var v = arr.get( 2 );

// returns false



v = arr.get( 3 );

// returns true



// Copy the first two elements to the last two elements using negative indices:

arr.copyWithin( -2, -4, -2 );



v = arr.get( 2 );

// returns true



v = arr.get( 3 );

// returns false

```






#### BooleanArray.prototype.entries()



Returns an iterator for iterating over array key-value pairs.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var it = arr.entries();



var v = it.next().value;

// returns [ 0, true ]



v = it.next().value;

// returns [ 1, false ]



v = it.next().value;

// returns [ 2, true ]



var bool = it.next().done;

// returns true

```



The returned [iterator][mdn-iterator-protocol] protocol-compliant object has the following properties:



-   **next**: function which returns an [iterator][mdn-iterator-protocol] protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the [iterator][mdn-iterator-protocol] is finished.

-   **return**: function which closes an [iterator][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.






#### BooleanArray.prototype.every( predicate\[, thisArg] )



Returns a boolean indicating whether all elements pass a test.



```javascript

function predicate( v ) {

    return v === true;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( true, 1 );

arr.set( true, 2 );



var bool = arr.every( predicate );

// returns true

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v ) {

    this.count += 1;

    return v === true;

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( true, 0 );

arr.set( true, 1 );

arr.set( true, 2 );



var bool = arr.every( predicate, context );

// returns true



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.fill( value\[, start\[, end]] )



Returns a modified typed array filled with a fill value.



```javascript

var arr = new BooleanArray( 3 );



// Set all elements to the same value:

arr.fill( true );



var v = arr.get( 0 );

// returns true



v = arr.get( 1 );

// returns true



v = arr.get( 2 );

// returns true



// Fill all elements starting from the second element:

arr.fill( false, 1 );



v = arr.get( 1 );

// returns false



v = arr.get( 2 );

// returns false



// Fill all elements from first element until the second-to-last element:

arr.fill( false, 0, 2 );



v = arr.get( 0 );

// returns false



v = arr.get( 1 );

// returns false

```



When a `start` and/or `end` index is negative, the respective index is determined relative to the last array element.



```javascript

var arr = new BooleanArray( 3 );



// Set all array elements, except the last element, to the same value:

arr.fill( true, 0, -1 );



var v = arr.get( 0 );

// returns true



v = arr.get( 2 );

// returns false

```






#### BooleanArray.prototype.filter( predicate\[, thisArg] )



Returns a new array containing the elements of an array which pass a test implemented by a predicate function.



```javascript

function predicate( v ) {

    return ( v === true );

}



var arr = new BooleanArray( 3 );



// Set the first three elements:

arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.filter( predicate );

// returns 



var len = out.length;

// returns 2



var v = out.get( 0 );

// returns true



v = out.get( 1 );

// return true

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v, i ) {

    this.count += 1;

    return ( v === true );

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.filter( predicate, context );

// returns 



var len = out.length;

// returns 2



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.find( predicate\[, thisArg] )



Returns the first element in an array for which a predicate function returns a truthy value.



```javascript

function predicate( v ) {

    return v === true;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var v = arr.find( predicate );

// returns true

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v ) {

    this.count += 1;

    return ( v === true );

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( false, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var z = arr.find( predicate, context );

// returns true



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.findIndex( predicate\[, thisArg] )



Returns the index of the first element in an array for which a predicate function returns a truthy value.



```javascript

function predicate( v ) {

    return v === true;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var v = arr.findIndex( predicate );

// returns 0

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v ) {

    this.count += 1;

    return ( v === true );

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( false, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var z = arr.findIndex( predicate, context );

// returns 2



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.findLast( predicate\[, thisArg] )



Returns the last element in an array for which a predicate function returns a truthy value.



```javascript

function predicate( v ) {

    return v === true;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var v = arr.findLast( predicate );

// returns true

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v ) {

    this.count += 1;

    return ( v === true );

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );



var z = arr.findLast( predicate, context );

// returns true



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.findLastIndex( predicate\[, thisArg] )



Returns the index of the last element in an array for which a predicate function returns a truthy value.



```javascript

function predicate( v ) {

    return v === true;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var v = arr.findLastIndex( predicate );

// returns 2

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v ) {

    this.count += 1;

    return ( v === true );

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );



var z = arr.findLastIndex( predicate, context );

// returns 0



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.forEach( callbackFn\[, thisArg] )



Invokes a function once for each array element.



```javascript

function log( v, i ) {

    console.log( '%s: %s', i.toString(), v.toString() );

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



arr.forEach( log );

/* =>

    0: true

    1: false

    2: true

*/

```



The invoked function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function fcn( v, i ) {

    this.count += 1;

    console.log( '%s: %s', i.toString(), v.toString() );

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



arr.forEach( fcn, context );



var count = context.count;

// returns 3

```






#### BooleanArray.prototype.get( i )



Returns an array element located at a nonnegative integer position (index) `i`.



```javascript

var arr = new BooleanArray( 10 );



// Set the first element:

arr.set( true, 0 );



// Get the first element:

var v = arr.get( 0 );

// returns true

```



If provided an out-of-bounds index, the method returns `undefined`.



```javascript

var arr = new BooleanArray( 10 );



var v = arr.get( 100 );

// returns undefined

```






#### BooleanArray.prototype.includes( searchElement\[, fromIndex] )



Returns a boolean indicating whether an array includes a provided value.



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( true, 3 );

arr.set( true, 4 );



var bool = arr.includes( true );

// returns true



bool = arr.includes( false, 2 );

// returns false

```






#### BooleanArray.prototype.indexOf( searchElement\[, fromIndex] )



Returns the first index at which a given element can be found.



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( true, 3 );

arr.set( true, 4 );



var idx = arr.indexOf( true );

// returns 0



idx = arr.indexOf( false, 1 );

// returns 1



idx = arr.indexOf( true, -3 );

// returns 2

```



If `searchElement` is not present in the array, the method returns `-1`.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( true, 1 );

arr.set( true, 2 );



var idx = arr.indexOf( false );

// returns -1

```






#### BooleanArray.prototype.join( \[separator] )



Returns a new string by concatenating all array elements.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var str = arr.join();

// returns 'true,false,true'

```



By default, the method separates serialized array elements with a comma. To use an alternative separator, provide a `separator` string.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var str = arr.join( '|' );

// returns 'true|false|true'

```






#### BooleanArray.prototype.keys()



Returns an iterator for iterating over each index key in a typed array.



```javascript

var arr = new BooleanArray( 2 );



arr.set( true, 0 );

arr.set( false, 1 );



var iter = arr.keys();



var v = iter.next().value;

// returns 0



v = iter.next().value;

// returns 1



var bool = iter.next().done;

// returns true

```



The returned [iterator][mdn-iterator-protocol] protocol-compliant object has the following properties:



-   **next**: function which returns an [iterator][mdn-iterator-protocol] protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the [iterator][mdn-iterator-protocol] is finished.

-   **return**: function which closes an [iterator][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.






#### BooleanArray.prototype.lastIndexOf( searchElement\[, fromIndex] )



Returns the last index at which a given element can be found.



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( true, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var idx = arr.lastIndexOf( true );

// returns 4



idx = arr.lastIndexOf( false, 3 );

// returns 3



idx = arr.lastIndexOf( true, -3 );

// returns 2

```



If `searchElement` is not present in the array, the method returns `-1`.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( true, 1 );

arr.set( true, 2 );



var idx = arr.lastIndexOf( false );

// returns -1

```






#### BooleanArray.prototype.map( callbackFn\[, thisArg] )



Returns a new array with each element being the result of a provided callback function.



```javascript

function invert( v ) {

    return !v;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.map( invert );

// returns 



var z = out.get( 0 );

// returns false



z = out.get( 1 );

// returns true



z = out.get( 2 );

// returns false

```



The callback function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function invert( v, i ) {

    this.count += i;

    return !v;

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.map( invert, context );

// returns 



var count = context.count;

// returns 3;

```






#### BooleanArray.prototype.reduce( reducerFn\[, initialValue] )



Applies a provided callback function to each element of the array, in order, passing in the return value from the calculation on the preceding element and returning the accumulated result upon completion.



```javascript

function reducer( acc, v ) {

    return ( acc && v );

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.reduce( reducer );

// returns false

```



The reducer function is provided four arguments:



-   **acc**: accumulated result.

-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



By default, the function initializes the accumulated result to the first element in the array and passes the second array element as `value` during the first invocation of the provided callback. To begin accumulation from a different starting value and pass in the first array element as `value` during the first invocation of the provided callback, provide an `initialValue` argument.



```javascript

function reducer( acc, v ) {

    if ( v ) {

        return acc + 1;

    }

    return acc;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.reduce( reducer, 0 );

// returns 2

```






#### BooleanArray.prototype.reduceRight( reducerFn\[, initialValue] )



Applies a provided callback function to each element of the array, in reverse order, passing in the return value from the calculation on the following element and returning the accumulated result upon completion.



```javascript

function reducer( acc, v ) {

    return ( acc && v );

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.reduceRight( reducer );

// returns false

```



The reducer function is provided four arguments:



-   **acc**: accumulated result.

-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



By default, the function initializes the accumulated result to the last element in the array and passes the second-last array element as `value` during the first invocation of the provided callback. To begin accumulation from a different starting value and pass in the last array element as `value` during the first invocation of the provided callback, provide an `initialValue` argument.



```javascript

function reducer( acc, v ) {

    if ( v ) {

        return acc + 1;

    }

    return acc;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.reduceRight( reducer, 0 );

// returns 2

```






#### BooleanArray.prototype.reverse()



Reverses an array in-place.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );



var out = arr.reverse();

// returns 



var v = out.get( 0 );

// returns false



v = out.get( 1 );

// returns false



v = out.get( 2 );

// returns true

```






#### BooleanArray.prototype.set( v\[, i] )



Sets one or more array elements.



```javascript

var arr = new BooleanArray( 10 );



// Get the first element:

var v = arr.get( 0 );

// returns false



// Set the first element:

arr.set( true );



// Get the first element:

v = arr.get( 0 );

// returns true

```



By default, the method sets array elements starting at position (index) `i = 0`. To set elements starting elsewhere in the array, provide an index argument `i`.



```javascript

var arr = new BooleanArray( 10 );



// Get the fifth element:

var v = arr.get( 4 );

// returns false



// Set the fifth element:

arr.set( true, 4 );



// Get the fifth element:

v = arr.get( 4 );

// returns true

```



In addition to providing a single value, to set one or more array elements, provide an array-like object containing truthy and falsy values



```javascript

var arr = new BooleanArray( 10 );



// Define an array of values:

var buf = [ '', 1, null ];



// Set the fifth, sixth, and seventh elements:

arr.set( buf, 4 );



// Get the sixth element:

var v = arr.get( 5 );

// returns true

```



A few notes:



-   If `i` is out-of-bounds, the method throws an error.

-   If a target array cannot accommodate all values (i.e., the length of source array plus `i` exceeds the target array length), the method throws an error.

-   If provided a [typed array][@stdlib/array/typed] which shares an [`ArrayBuffer`][@stdlib/array/buffer] with the target array, the method will intelligently copy the source range to the destination range.






#### BooleanArray.prototype.slice( \[start\[, end]] )



Copies a portion of a typed array to a new typed array.



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var out = arr.slice();

// returns 



var len = out.length;

// returns 5



var bool = out.get( 0 );

// returns true



bool = out.get( len-1 );

// returns true

```



By default, the method returns a typed array beginning with the first array element. To specify an alternative array index at which to begin, provide a `start` index (inclusive).



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var out = arr.slice( 1 );

// returns 



var len = out.length;

// returns 4



var bool = out.get( 0 );

// returns false



bool = out.get( len-1 );

// returns true

```



By default, the method returns a typed array which includes all array elements after `start`. To limit the number of array elements after `start`, provide an `end` index (exclusive).



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var out = arr.slice( 1, -2 );

// returns 



var len = out.length;

// returns 2



var bool = out.get( 0 );

// returns false



bool = out.get( len-1 );

// returns true

```






#### BooleanArray.prototype.some( predicate\[, thisArg] )



Returns a boolean indicating whether at least one element passes a test.



```javascript

function predicate( v ) {

    return v === true;

}



var arr = new BooleanArray( 3 );



arr.set( false, 0 );

arr.set( true, 1 );

arr.set( false, 2 );



var bool = arr.some( predicate );

// returns true

```



The `predicate` function is provided three arguments:



-   **value**: current array element.

-   **index**: current array element index.

-   **arr**: the array on which this method was called.



To set the function execution context, provide a `thisArg`.



```javascript

function predicate( v ) {

    this.count += 1;

    return v === true;

}



var arr = new BooleanArray( 3 );



var context = {

    'count': 0

};



arr.set( false, 0 );

arr.set( true, 1 );

arr.set( false, 2 );



var bool = arr.some( predicate, context );

// returns true



var count = context.count;

// returns 2

```






#### BooleanArray.prototype.sort( \[compareFcn] )



Sorts an array in-place.



```javascript

function compare( a, b ) {

    if ( a === false ) {

        if ( b === false ) {

            return 0;

        }

        return 1;

    }

    if ( b === true ) {

        return 0;

    }

    return -1;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



arr.sort( compare );



var v = arr.get( 0 );

// returns true



v = arr.get( 1 );

// returns true



v = arr.get( 2 );

// returns false

```



The `compareFcn` determines the order of the elements. The function is called with the following arguments:



-   **a**: the first boolean value for comparison.

-   **b**: the second boolean value for comparison.



The function should return a number where:



-   a negative value indicates that `a` should come before `b`.

-   a positive value indicates that `a` should come after `b`.

-   zero or `NaN` indicates that `a` and `b` are considered equal.






#### BooleanArray.prototype.subarray( \[begin\[, end]] )



Creates a new typed array view over the same underlying [`ArrayBuffer`][@stdlib/array/buffer] and with the same underlying data type as the host array.



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var subarr = arr.subarray();

// returns 



var len = subarr.length;

// returns 5



var bool = subarr.get( 0 );

// returns true



bool = subarr.get( len-1 );

// returns true

```



By default, the method creates a typed array view beginning with the first array element. To specify an alternative array index at which to begin, provide a `begin` index (inclusive).



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var subarr = arr.subarray( 1 );

// returns 



var len = subarr.length;

// returns 4



var bool = subarr.get( 0 );

// returns false



bool = subarr.get( len-1 );

// returns true

```



By default, the method creates a typed array view which includes all array elements after `begin`. To limit the number of array elements after `begin`, provide an `end` index (exclusive).



```javascript

var arr = new BooleanArray( 5 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );

arr.set( false, 3 );

arr.set( true, 4 );



var subarr = arr.subarray( 1, -2 );

// returns 



var len = subarr.length;

// returns 2



var bool = subarr.get( 0 );

// returns false



bool = subarr.get( len-1 );

// returns true

```






#### BooleanArray.prototype.toLocaleString( \[locales\[, options]] )



Serializes an array as a locale-specific string.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var str = arr.toLocaleString();

// returns 'true,false,true'

```



The method supports the following arguments:



-   **locales**: a string with a BCP 47 language tag or an array of such strings.

-   **options**: configuration properties.






#### BooleanArray.prototype.toReversed()



Returns a new typed array containing the elements in reversed order.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( false, 2 );



var out = arr.toReversed();

// returns 



var v = out.get( 0 );

// returns false



v = out.get( 1 );

// returns false



v = out.get( 2 );

// returns true

```






#### BooleanArray.prototype.toSorted( \[compareFcn] )



Returns a new typed array containing the elements in sorted order.



```javascript

function compare( a, b ) {

    if ( a === false ) {

        if ( b === false ) {

            return 0;

        }

        return 1;

    }

    if ( b === true ) {

        return 0;

    }

    return -1;

}



var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var out = arr.sort( compare );

// returns 



var v = out.get( 0 );

// returns true



v = out.get( 1 );

// returns true



v = out.get( 2 );

// returns false

```



The `compareFcn` determines the order of the elements. The function is called with the following arguments:



-   **a**: the first boolean value for comparison.

-   **b**: the second boolean value for comparison.



The function should return a number where:



-   a negative value indicates that `a` should come before `b`.

-   a positive value indicates that `a` should come after `b`.

-   zero or `NaN` indicates that `a` and `b` are considered equal.






#### BooleanArray.prototype.toString()



Serializes an array as a string.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 2 );



var str = arr.toString();

// returns 'true,false,true'

```






#### BooleanArray.prototype.values()



Returns an iterator for iterating over each value in a typed array.



```javascript

var arr = new BooleanArray( 2 );



arr.set( true, 0 );

arr.set( false, 1 );



var iter = arr.values();



var v = iter.next().value;

// returns true



v = iter.next().value;

// returns false



var bool = iter.next().done;

// returns true

```



The returned [iterator][mdn-iterator-protocol] protocol-compliant object has the following properties:



-   **next**: function which returns an [iterator][mdn-iterator-protocol] protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the [iterator][mdn-iterator-protocol] is finished.

-   **return**: function which closes an [iterator][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.






#### BooleanArray.prototype.with( index, value )



Returns a new typed array with the element at a provided index replaced with a provided value.



```javascript

var arr = new BooleanArray( 3 );



arr.set( true, 0 );

arr.set( false, 1 );

arr.set( true, 1 );



var out = arr.with( 0, false );

// returns 



var v = out.get( 0 );

// returns false

```



* * *



## Notes



-   While a `BooleanArray` _strives_ to maintain (but does not **guarantee**) consistency with [typed arrays][@stdlib/array/typed], significant deviations from ECMAScript-defined [typed array][@stdlib/array/typed] behavior are as follows:



    -   The constructor does **not** require the `new` operator.

    -   Accessing array elements using bracket syntax (e.g., `X[i]`) is **not** supported. Instead, one **must** use the `.get()` method.



* * *



## Examples



```javascript

var Uint8Array = require( '@stdlib/array-uint8' );

var logEach = require( '@stdlib/console-log-each' );

var BooleanArray = require( '@stdlib/array-bool' );



// Create a boolean array by specifying a length:

var out = new BooleanArray( 3 );

logEach( '%s', out );



// Create a boolean array from an array of booleans:

var arr = [ true, false, true ];

out = new BooleanArray( arr );

logEach( '%s', out );



// Create a boolean array from an array buffer:

arr = new Uint8Array( [ 1, 0, 1, 1, 0, 1 ] );

out = new BooleanArray( arr.buffer );

logEach( '%s', out );



// Create a boolean array from an array buffer view:

arr = new Uint8Array( [ 1, 0, 1, 1, 0, 1 ] );

out = new BooleanArray( arr.buffer, 1, 2 );

logEach( '%s', out );



console.log( '%s', false );

```



* * *



## See Also



-   [`@stdlib/array-buffer`][@stdlib/array/buffer]: ArrayBuffer.



* * *



## Notice



This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.



For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].



#### Community



[![Chat][chat-image]][chat-url]



---



## License



See [LICENSE][stdlib-license].



## Copyright



Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].



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[npm-url]: https://npmjs.org/package/@stdlib/array-bool



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[stdlib]: https://github.com/stdlib-js/stdlib



[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors



[umd]: https://github.com/umdjs/umd

[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules



[deno-url]: https://github.com/stdlib-js/array-bool/tree/deno

[deno-readme]: https://github.com/stdlib-js/array-bool/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/array-bool/tree/umd

[umd-readme]: https://github.com/stdlib-js/array-bool/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/array-bool/tree/esm

[esm-readme]: https://github.com/stdlib-js/array-bool/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/array-bool/blob/main/branches.md



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/array-bool/main/LICENSE



[mdn-iterator-protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterator_protocol



[@stdlib/array/typed]: https://github.com/stdlib-js/array-typed



[@stdlib/array/buffer]: https://github.com/stdlib-js/array-buffer