object_mode.js (2176B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var isObject = require( '@stdlib/assert/is-plain-object' ); 24 var copy = require( '@stdlib/utils/copy' ); 25 var IteratorStream = require( './main.js' ); 26 27 28 // MAIN // 29 30 /** 31 * Returns an "objectMode" readable stream from an iterator. 32 * 33 * @param {Iterator} iterator - source iterator 34 * @param {Options} [options] - stream options 35 * @param {(string|null)} [options.encoding=null] - specifies how `Buffer` objects should be decoded to `strings` 36 * @param {NonNegativeNumber} [options.highWaterMark] - specifies the maximum number of objects to store in an internal buffer before pausing iteration 37 * @throws {TypeError} first argument must be an iterator 38 * @throws {TypeError} options argument must be an object 39 * @throws {TypeError} must provide valid options 40 * @returns {IteratorStream} Stream instance 41 * 42 * @example 43 * var randu = require( '@stdlib/random/iter/randu' ); 44 * var inspectStream = require( '@stdlib/streams/node/inspect-sink' ); 45 * 46 * function log( v ) { 47 * console.log( v ); 48 * } 49 * 50 * var opts = { 51 * 'iter': 10 52 * }; 53 * 54 * var stream = objectMode( randu( opts ) ); 55 * 56 * stream.pipe( inspectStream.objectMode( log ) ); 57 */ 58 function objectMode( iterator, options ) { 59 var opts; 60 if ( arguments.length > 1 ) { 61 opts = options; 62 if ( !isObject( opts ) ) { 63 throw new TypeError( 'invalid argument. Options must be an object. Value: `' + opts + '`.' ); 64 } 65 opts = copy( options, 1 ); 66 } else { 67 opts = {}; 68 } 69 opts.objectMode = true; 70 return new IteratorStream( iterator, opts ); 71 } 72 73 74 // EXPORTS // 75 76 module.exports = objectMode;