time-to-botec

README.md (7002B)

---

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 @license Apache-2.0
 
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 See the License for the specific language governing permissions and
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 # Circular Array Stream
 
 > Create a [readable stream][readable-stream] from a circular array-like object.
 
 <section class="usage">
 
 ## Usage
 
 ```javascript
 var circularArrayStream = require( '@stdlib/streams/node/from-circular-array' );
 ```
 
 <a name="circular-array-stream"></a>
 
 #### 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`.
 
 </section>
 
 <!-- /.usage -->
 
 * * *
 
 <section class="notes">
 
 ## 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.
 
 </section>
 
 <!-- /.notes -->
 
 * * *
 
 <section class="examples">
 
 ## Examples
 
 <!-- eslint no-undef: "error" -->
 
 ```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 );
 ```
 
 </section>
 
 <!-- /.examples -->
 
 <section class="links">
 
 [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
 
 </section>
 
 <!-- /.links -->