@stdlib/streams-node-from-strided-array
v0.2.2
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Create a readable stream from a strided array-like object.
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Strided Array Stream
Create a readable stream from a strided array-like object.
Installation
npm install @stdlib/streams-node-from-strided-array
Usage
var stridedArrayStream = require( '@stdlib/streams-node-from-strided-array' );
stridedArrayStream( N, buffer, stride, offset[, options] )
Returns a readable stream from a strided array-like object
.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( chunk ) {
console.log( chunk.toString() );
}
var stream = stridedArrayStream( 4, [ 1, 2, 3, 4 ], 1, 0 );
var iStream = inspectStream( log );
stream.pipe( iStream );
The function accepts the following options
:
- objectMode: specifies whether a stream should operate in objectMode. Default:
false
. - encoding: specifies how
Buffer
objects should be decoded tostrings
. 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. Default:
'\n'
. - serialize: custom serialization function. This option is only applicable when a stream is not in objectMode.
To set stream options
,
var opts = {
'objectMode': true,
'encoding': 'utf8',
'highWaterMark': 64
};
var stream = stridedArrayStream( 4, [ 1, 2, 3, 4 ], 1, 0, opts );
By default, when not operating in objectMode, a returned stream delineates individual values using a newline character. To specify an alternative separator, set the sep
option.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( chunk ) {
console.log( chunk.toString() );
}
var stream = stridedArrayStream( 4, [ 1, 2, 3, 4 ], 1, 0, {
'sep': ','
});
var iStream = inspectStream( log );
stream.pipe( iStream );
By default, when not operating in objectMode, a returned stream serializes values as JSON strings. To specify custom serialization behavior (either to a string
or Buffer
), set the serialize
option.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function serialize( v ) {
return 'v::' + v.toString();
}
function log( chunk ) {
console.log( chunk.toString() );
}
var stream = stridedArrayStream( 4, [ 1, 2, 3, 4 ], 1, 0, {
'serialize': serialize
});
var iStream = inspectStream( log );
stream.pipe( iStream );
stridedArrayStream.factory( [options] )
Returns a function
for creating readable streams from strided array-like objects.
var opts = {
'objectMode': true,
'encoding': 'utf8',
'highWaterMark': 64
};
var createStream = stridedArrayStream.factory( opts );
var stream1 = createStream( 2, [ 1, 2, 3, 4 ], 2, 1 );
var stream2 = createStream( 3, [ 5, 6, 7, 8 ], 1, 1 );
// ...
The method accepts the same options
as stridedArrayStream()
.
stridedArrayStream.objectMode( N, buffer, stride, offset[, options] )
This method is a convenience function to create streams which always operate in objectMode.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( v ) {
console.log( v );
}
var stream = stridedArrayStream.objectMode( 4, [ 1, 2, 3, 4 ], 1, 0 );
var opts = {
'objectMode': true
};
var iStream = inspectStream( opts, log );
stream.pipe( iStream );
This method accepts the same options
as stridedArrayStream()
; however, the method will always override the objectMode
option in options
.
Notes
- In
objectMode
,null
is a reserved value. If anarray
containsnull
values (e.g., as a means to encode missing values), the stream will prematurely end. Consider an alternative encoding or filternull
values prior to invocation. - In binary mode, if an
array
containsundefined
values, the stream will emit an error. Consider providing a custom serialization function or filteringundefined
values prior to invocation.
Examples
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
var randu = require( '@stdlib/random-base-randu' );
var Float64Array = require( '@stdlib/array-float64' );
var stridedArrayStream = require( '@stdlib/streams-node-from-strided-array' );
function log( v ) {
console.log( v.toString() );
}
// Create an array containing uniformly distributed pseudorandom numbers:
var arr = new Float64Array( 20 );
var i;
for ( i = 0; i < arr.length; i++ ) {
arr[ i ] = randu();
}
// Create a stream which iterates over every other element from right-to-left:
var opts = {
'objectMode': true
};
var stream = stridedArrayStream( 10, arr, -2, arr.length-2, 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
: create a readable stream from an array-like object.
Notice
This package is part of 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, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.