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https://github.com/stdlib-js/streams-node-from-circular-array
Create a readable stream from a circular array-like object.
https://github.com/stdlib-js/streams-node-from-circular-array
array array-like convert from javascript node node-js nodejs readable stdlib stream streams string typed typed-array util utilities utility utils
Last synced: 21 days ago
JSON representation
Create a readable stream from a circular array-like object.
- Host: GitHub
- URL: https://github.com/stdlib-js/streams-node-from-circular-array
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-15T17:46:59.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2024-10-01T09:01:00.000Z (3 months ago)
- Last Synced: 2024-10-30T05:35:39.444Z (about 2 months ago)
- Topics: array, array-like, convert, from, javascript, node, node-js, nodejs, readable, stdlib, stream, streams, string, typed, typed-array, util, utilities, utility, utils
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.51 MB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
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# Circular Array Stream
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Create a [readable stream][readable-stream] from a circular array-like object.
## Installation
```bash
npm install @stdlib/streams-node-from-circular-array
```
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 circularArrayStream = require( '@stdlib/streams-node-from-circular-array' );
```
#### circularArrayStream( src\[, options] )
Returns a [readable stream][readable-stream] from an array-like `object` which repeatedly iterates over a provided value's elements.
```javascript
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
var iStream;
var stream;
var count;
function log( chunk ) {
console.log( chunk.toString() );
count += 1;
if ( count === 20 ) {
stream.destroy();
}
}
stream = circularArrayStream( [ 1, 2, 3, 4 ] );
iStream = inspectStream( log );
count = 0;
stream.pipe( iStream );
```
The function accepts the following `options`:
- **objectMode**: specifies whether a [stream][stream] should operate in [objectMode][object-mode]. Default: `false`.
- **encoding**: specifies how `Buffer` objects should be decoded to `strings`. Default: `null`.
- **highWaterMark**: specifies the maximum number of bytes to store in an internal buffer before pausing streaming.
- **sep**: separator used to join streamed data. This option is only applicable when a stream is **not** in [objectMode][object-mode]. Default: `'\n'`.
- **serialize**: custom serialization function. This option is only applicable when a stream is **not** in [objectMode][object-mode].
- **iter**: number of iterations. Default: `1e308`.
- **dir**: iteration direction. If set to `-1`, the stream iterates over elements from right-to-left. Default: `1`.
To set [stream][stream] `options`,
```javascript
var opts = {
'objectMode': true,
'encoding': 'utf8',
'highWaterMark': 64
};
var stream = circularArrayStream( [ 1, 2, 3, 4 ], opts );
```
By default, the returned [stream][stream] is an infinite stream (i.e., never ends). To limit the number of streamed values, set the `iter` option.
```javascript
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( chunk ) {
console.log( chunk.toString() );
}
var opts = {
'iter': 10
};
var stream = circularArrayStream( [ 1, 2, 3, 4 ], opts );
var iStream = inspectStream( log );
stream.pipe( iStream );
```
By default, when not operating in [objectMode][object-mode], a returned [stream][stream] delineates individual values using a newline character. To specify an alternative separator, set the `sep` option.
```javascript
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( chunk ) {
console.log( chunk.toString() );
}
var stream = circularArrayStream( [ 1, 2, 3, 4 ], {
'sep': ',',
'iter': 10
});
var iStream = inspectStream( log );
stream.pipe( iStream );
```
By default, when not operating in [objectMode][object-mode], a returned [stream][stream] serializes values as JSON strings. To specify custom serialization behavior (either to a `string` or `Buffer`), set the `serialize` option.
```javascript
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function serialize( v ) {
return 'v::' + v.toString();
}
function log( chunk ) {
console.log( chunk.toString() );
}
var stream = circularArrayStream( [ 1, 2, 3, 4 ], {
'serialize': serialize,
'iter': 10
});
var iStream = inspectStream( log );
stream.pipe( iStream );
```
* * *
#### circularArrayStream.factory( \[options] )
Returns a `function` for creating [readable streams][readable-stream] from array-like objects.
```javascript
var opts = {
'objectMode': true,
'encoding': 'utf8',
'highWaterMark': 64
};
var createStream = circularArrayStream.factory( opts );
var stream1 = createStream( [ 1, 2, 3, 4 ] );
var stream2 = createStream( [ 5, 6, 7, 8 ] );
// ...
```
The method accepts the same `options` as [`circularArrayStream()`](#circular-array-stream).
* * *
#### circularArrayStream.objectMode( src\[, options] )
This method is a convenience function to create [streams][stream] which **always** operate in [objectMode][object-mode].
```javascript
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( v ) {
console.log( v );
}
var opts = {
'iter': 10
};
var stream = circularArrayStream.objectMode( [ 1, 2, 3, 4 ], opts );
opts = {
'objectMode': true
};
var iStream = inspectStream( opts, log );
stream.pipe( iStream );
```
This method accepts the same `options` as [`circularArrayStream()`](#circular-array-stream); however, the method will **always** override the [`objectMode`][object-mode] option in `options`.
* * *
## Notes
- In [`objectMode`][object-mode], `null` is a reserved value. If an `array` contains `null` values (e.g., as a means to encode missing values), the stream will prematurely end. Consider an alternative encoding or filter `null` values prior to invocation.
- In binary mode, if an `array` contains `undefined` values, the stream will emit an error. Consider providing a custom serialization function or filtering `undefined` values prior to invocation.
* * *
## Examples
```javascript
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
var randu = require( '@stdlib/random-base-randu' );
var Float64Array = require( '@stdlib/array-float64' );
var circularArrayStream = require( '@stdlib/streams-node-from-circular-array' );
function log( v ) {
console.log( v.toString() );
}
// Create an array containing uniformly distributed pseudorandom numbers:
var arr = new Float64Array( 10 );
var i;
for ( i = 0; i < arr.length; i++ ) {
arr[ i ] = randu();
}
// Convert the array to a stream:
var opts = {
'objectMode': true,
'iter': arr.length * 3
};
var stream = circularArrayStream( arr, opts );
// Create a writable stream for inspecting stream data:
opts = {
'objectMode': true
};
var iStream = inspectStream( opts, log );
// Begin data flow:
stream.pipe( iStream );
```
* * *
## See Also
- [`@stdlib/streams-node/from-array`][@stdlib/streams/node/from-array]: create a readable stream from an array-like object.
- [`@stdlib/streams-node/from-iterator`][@stdlib/streams/node/from-iterator]: create a readable stream from an iterator.
- [`@stdlib/streams-node/from-strided-array`][@stdlib/streams/node/from-strided-array]: create a readable stream from a strided array-like object.
* * *
## 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 © 2016-2024. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/streams-node-from-circular-array.svg
[npm-url]: https://npmjs.org/package/@stdlib/streams-node-from-circular-array
[test-image]: https://github.com/stdlib-js/streams-node-from-circular-array/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/streams-node-from-circular-array/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/streams-node-from-circular-array/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/streams-node-from-circular-array?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[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/streams-node-from-circular-array/tree/deno
[deno-readme]: https://github.com/stdlib-js/streams-node-from-circular-array/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/streams-node-from-circular-array/tree/umd
[umd-readme]: https://github.com/stdlib-js/streams-node-from-circular-array/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/streams-node-from-circular-array/tree/esm
[esm-readme]: https://github.com/stdlib-js/streams-node-from-circular-array/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/streams-node-from-circular-array/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/streams-node-from-circular-array/main/LICENSE
[stream]: https://nodejs.org/api/stream.html
[object-mode]: https://nodejs.org/api/stream.html#stream_object_mode
[readable-stream]: https://nodejs.org/api/stream.html
[@stdlib/streams/node/from-array]: https://github.com/stdlib-js/streams-node-from-array
[@stdlib/streams/node/from-iterator]: https://github.com/stdlib-js/streams-node-from-iterator
[@stdlib/streams/node/from-strided-array]: https://github.com/stdlib-js/streams-node-from-strided-array