https://github.com/mikolalysenko/generic-slice

Generic array-like slice for TypedArrays, Buffers and Arguments
https://github.com/mikolalysenko/generic-slice

Last synced: 6 days ago
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Generic array-like slice for TypedArrays, Buffers and Arguments

• Host: GitHub
• URL: https://github.com/mikolalysenko/generic-slice
• Owner: mikolalysenko
• License: mit
• Created: 2013-04-07T21:42:33.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-05-14T00:11:59.000Z (over 11 years ago)
• Last Synced: 2024-12-16T22:34:57.545Z (9 days ago)
• Language: JavaScript
• Size: 121 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
generic-slice

=============

A poly fill for [`slice`](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/slice) that uniformly and efficiently implements `Array`-like semantics for the following classses of objects:

* Typed Arrays

* Node.JS-style `Buffers()`

* Regular JS Arrays

* Arguments

* Any other array-like object (ie has a length and array accessors)

## Install

    npm install generic-slice

    

## Example

```javascript

var slice = require("generic-slice")

var x = new Float32Array(4)

x[0] = 1

x[1] = 2

x[2] = 3

x[3] = 4

var y = slice(x, 0, 2)

// Now:

//      y = [ 1, 2 ]

//      x = [ 1, 2, 3, 4 ]

y[0] = 1000

// Now:

//      y = [ 1000, 2 ]

//      x = [ 1, 2, 3, 4 ]

```

### `require("generic-slice")(array[, sliceBegin, sliceEnd])`

A generic polyfill for slicing array-like objects.

* `array` is a typed array, buffer, Array, or Arguments object

* `sliceBegin` is an optional argument giving the start of the slice. Negative values change counting to end of array.  (Default: 0)

* `sliceEnd` is an optional argument giving the end of the slice.  Negative values wrap around.  (Default: array.length)

**Returns** A copy of the array from the range `[sliceBegin, sliceEnd)`

### Why make this?

Because:

* `slice` got dropped from the typed array specification (and the replacement method, `.subarray()` merely returns a view and does not make a copy)

* Node.JS's `Buffer`'s slice method does not make a copy like Array's slice does, and so it has inconsistent semantics.

* `Arguments` doesn't have a slice method either

* Using `Array.prototype.slice.call` doesn't properly preserve the types of things like Buffers or typed arrays

* Also `Array.prototype.slice.call` can be slower than an appropriate implementation.  For example, to clone a typed array you can slice the underlying ArrayBuffer assuming that you are careful about how you perform indexing.

### Is it thoroughly tested?

All of the major edge cases should be tested.  If you find a bug, please open an issue or send a pull request.

# Credits

(c) 2013 Mikola Lysenko. MIT License