time-to-botec

README.md (5487B)

---

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 @license Apache-2.0
 
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 Licensed under the Apache License, Version 2.0 (the "License");
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 See the License for the specific language governing permissions and
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 # Inspect Stream
 
 > [Writable stream][writable-stream] for inspecting streamed data.
 
 <section class="usage">
 
 ## Usage
 
 ```javascript
 var inspectSinkStream = require( '@stdlib/streams/node/inspect-sink' );
 ```
 
 <a name="inspect-sink-stream"></a>
 
 #### inspectSinkStream( \[options,] clbk )
 
 Creates a [writable stream][writable-stream] for inspecting streamed data.
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var stream = inspectSinkStream( log );
 
 stream.write( 'a' );
 stream.write( 'b' );
 stream.write( 'c' );
 
 stream.end();
 
 // prints: index: 0
 // prints: a
 // prints: index: 1
 // prints: b
 // prints: index: 2
 // prints: c
 ```
 
 The function accepts the following `options`:
 
 -   **objectMode**: specifies whether a [stream][stream] should operate in [objectMode][object-mode]. Default: `false`.
 -   **highWaterMark**: specifies the `Buffer` level at which `write()` calls start returning `false`.
 -   **decodeStrings**: specifies whether to encode strings as `Buffer` objects before writing data to a returned [stream][stream]. Default: `true`.
 -   **defaultEncoding**: default encoding when not explicitly specified when writing data. Default: `'utf8'`.
 
 To set [stream][stream] `options`,
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var opts = {
     'objectMode': true,
     'highWaterMark': 64,
     'decodeStrings': false,
     'defaultEncoding': 'utf8'
 };
 
 var stream = inspectSinkStream( opts, log );
 ```
 
 #### inspectSinkStream.factory( \[options] )
 
 Returns a `function` for creating [streams][writable-stream] which are identically configured according to provided `options`.
 
 ```javascript
 var opts = {
     'objectMode': true,
     'highWaterMark': 64
 };
 
 var factory = inspectSinkStream.factory( opts );
 ```
 
 This method accepts the same `options` as [`inspectSinkStream()`](#inspect-sink-stream).
 
 ##### factory( clbk )
 
 Creates a [writable stream][writable-stream] for inspecting streamed data.
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var factory = inspectSinkStream.factory();
 
 // Create 10 identically configured streams...
 var streams = [];
 var i;
 for ( i = 0; i < 10; i++ ) {
     streams.push( factory( log ) );
 }
 ```
 
 #### inspectSinkStream.objectMode( \[options,] clbk )
 
 This method is a convenience function to create [streams][stream] which **always** operate in [objectMode][object-mode].
 
 <!-- eslint-disable object-curly-newline -->
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var stream = inspectSinkStream.objectMode( log );
 
 stream.write( { 'value': 'a' } );
 stream.write( { 'value': 'b' } );
 stream.write( { 'value': 'c' } );
 
 stream.end();
 
 // prints: index: 0
 // prints: {'value': 'a'}
 // prints: index: 1
 // prints: {'value': 'b'}
 // prints: index: 2
 // prints: {'value': 'c'}
 ```
 
 This method accepts the same `options` as [`inspectSinkStream()`](#inspect-sink-stream); however, the method will **always** override the [objectMode][object-mode] option in `options`.
 
 </section>
 
 <!-- /.usage -->
 
 <section class="examples">
 
 ## Examples
 
 <!-- eslint no-undef: "error" -->
 
 ```javascript
 var parseJSON = require( '@stdlib/utils/parse-json' );
 var transformFactory = require( '@stdlib/streams/node/transform' ).factory;
 var inspect = require( '@stdlib/streams/node/inspect-sink' ).objectMode;
 
 function parse( chunk, enc, clbk ) {
     clbk( null, parseJSON( chunk ) );
 }
 
 function pluck( chunk, enc, clbk ) {
     clbk( null, chunk.value );
 }
 
 function square( chunk, enc, clbk ) {
     var v = +chunk;
     clbk( null, v*v );
 }
 
 function toStr( chunk, enc, clbk ) {
     clbk( null, chunk.toString() );
 }
 
 function join( chunk, enc, clbk ) {
     clbk( null, chunk+'\n' );
 }
 
 function logger( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 // Create a factory for generating streams running in `objectMode`:
 var tStream = transformFactory({
     'objectMode': true
 });
 
 // Create streams for each transform:
 var s1 = tStream( parse );
 var s2 = tStream( pluck );
 var s3 = tStream( square );
 var s4 = tStream( toStr );
 var s5 = tStream( join );
 
 // Create a writable stream for inspecting the result of the transformations:
 var is = inspect( logger );
 
 // Create the pipeline:
 s1.pipe( s2 )
     .pipe( s3 )
     .pipe( s4 )
     .pipe( s5 )
     .pipe( is );
 
 // Write data to the pipeline...
 var v;
 var i;
 for ( i = 0; i < 100; i++ ) {
     v = '{"value":'+i+'}';
     s1.write( v, 'utf8' );
 }
 s1.end();
 ```
 
 </section>
 
 <!-- /.examples -->
 
 <section class="links">
 
 [stream]: https://nodejs.org/api/stream.html
 
 [object-mode]: https://nodejs.org/api/stream.html#stream_object_mode
 
 [writable-stream]: https://nodejs.org/api/stream.html
 
 </section>
 
 <!-- /.links -->