time-to-botec

README.md (5702B)

---

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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
 
 > [Transform stream][transform-stream] for inspecting streamed data.
 
 <section class="usage">
 
 ## Usage
 
 ```javascript
 var inspectStream = require( '@stdlib/streams/node/inspect' );
 ```
 
 <a name="inspect-stream"></a>
 
 #### inspectStream( \[options,] clbk )
 
 Creates a [transform stream][transform-stream] for inspecting streamed data.
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var stream = inspectStream( log );
 
 stream.write( 'a' );
 stream.write( 'b' );
 stream.write( 'c' );
 
 stream.end();
 /* =>
 'index: 0'
 'a'
 'index: 1'
 'b'
 'index: 2'
 '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`.
 -   **allowHalfOpen**: specifies whether a [stream][stream] should remain open even if one side ends. Default: `false`.
 -   **readableObjectMode**: specifies whether the readable side should be in [objectMode][object-mode]. Default: `false`.
 
 To set [stream][stream] `options`,
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var opts = {
     'objectMode': true,
     'highWaterMark': 64,
     'allowHalfOpen': true,
     'readableObjectMode': false // overridden by `objectMode` option when `objectMode=true`
 };
 
 var stream = inspectStream( opts, log );
 ```
 
 #### inspectStream.factory( \[options] )
 
 Returns a `function` for creating [streams][transform-stream] which are identically configured according to provided `options`.
 
 ```javascript
 var opts = {
     'objectMode': true,
     'highWaterMark': 64
 };
 
 var factory = inspectStream.factory( opts );
 ```
 
 This method accepts the same `options` as [`inspectStream()`](#inspect-stream).
 
 ##### factory( clbk )
 
 Creates a [transform stream][transform-stream] for inspecting streamed data.
 
 ```javascript
 function log( chunk, idx ) {
     console.log( 'index: %d', idx );
     console.log( chunk );
 }
 
 var factory = inspectStream.factory();
 
 // Create 10 identically configured streams...
 var streams = [];
 var i;
 for ( i = 0; i < 10; i++ ) {
     streams.push( factory( log ) );
 }
 ```
 
 #### inspectStream.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 = inspectStream.objectMode( log );
 
 stream.write( { 'value': 'a' } );
 stream.write( { 'value': 'b' } );
 stream.write( { 'value': 'c' } );
 
 stream.end();
 /* =>
 'index: 0'
 {'value': 'a'}
 'index: 1'
 {'value': 'b'}
 'index: 2'
 {'value': 'c'}
 */
 ```
 
 This method accepts the same `options` as [`inspectStream()`](#inspect-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 stdout = require( '@stdlib/streams/node/stdout' );
 var transformFactory = require( '@stdlib/streams/node/transform' ).factory;
 var inspect = require( '@stdlib/streams/node/inspect' ).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( name ) {
     return log;
 
     function log( chunk, idx ) {
         console.log( 'name: %s', name );
         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 i1 = inspect( logger( 'parse' ) );
 var s2 = tStream( pluck );
 var i2 = inspect( logger( 'pluck' ) );
 var s3 = tStream( square );
 var i3 = inspect( logger( 'square' ) );
 var s4 = tStream( toStr );
 var i4 = inspect( logger( 'toString' ) );
 var s5 = tStream( join );
 var i5 = inspect( logger( 'join' ) );
 
 // Create the pipeline:
 s1.pipe( i1 )
     .pipe( s2 )
     .pipe( i2 )
     .pipe( s3 )
     .pipe( i3 )
     .pipe( s4 )
     .pipe( i4 )
     .pipe( s5 )
     .pipe( i5 )
     .pipe( stdout );
 
 // 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
 
 [transform-stream]: https://nodejs.org/api/stream.html
 
 </section>
 
 <!-- /.links -->