159 lines
3.5 KiB
JavaScript
159 lines
3.5 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var isFunction = require( '@stdlib/assert/is-function' );
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var isString = require( '@stdlib/assert/is-string' ).isPrimitive;
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var Buffer = require( '@stdlib/buffer/ctor' );
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var string2buffer = require( '@stdlib/buffer/from-string' );
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var stream = require( '@stdlib/streams/node/stdin' );
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var nextTick = require( '@stdlib/utils/next-tick' );
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// MAIN //
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/**
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* Reads data from `stdin`.
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*
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* @param {(string|null)} [encoding] - string encoding. If set, data will be returned as an encoded `string`.
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* @param {Function} clbk - callback to be invoked upon reading all data from `stdin`
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* @throws {TypeError} `encoding` argument must be a string
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* @throws {TypeError} callback argument must be a function
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* @returns {void}
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*
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* @example
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* function onRead( error, data ) {
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* if ( error ) {
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* throw error;
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* }
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* console.log( data.toString() );
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* // => '...'
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* }
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*
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* stdin( onRead );
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*
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* @example
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* function onRead( error, data ) {
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* if ( error ) {
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* throw error;
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* }
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* console.log( data );
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* // => '...'
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* }
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*
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* stdin( 'utf8', onRead );
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*/
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function stdin() {
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var clbk;
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var data;
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var enc;
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var len;
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if ( arguments.length === 1 ) {
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clbk = arguments[ 0 ];
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} else {
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enc = arguments[ 0 ];
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if ( !isString( enc ) ) {
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throw new TypeError( 'invalid argument. Encoding argument must be a string. Value: `' + enc + '`.' );
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}
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clbk = arguments[ 1 ];
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}
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if ( !isFunction( clbk ) ) {
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throw new TypeError( 'invalid argument. Callback argument must be a function. Value: `' + clbk + '`.' );
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}
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if ( enc ) {
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stream.setEncoding( enc );
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}
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// If the calling file is being run as a script and not as part of a pipeline, we should not expect to receive anything on `stdin`.
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if ( stream.isTTY ) {
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return nextTick( onTick );
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}
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data = [];
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len = 0;
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stream.on( 'readable', onReadable );
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stream.on( 'error', onError );
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stream.on( 'end', onEnd );
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/**
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* Callback invoked after the next tick.
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*
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* @private
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* @returns {void}
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*/
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function onTick() {
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if ( enc ) {
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return clbk( null, '' );
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}
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clbk( null, string2buffer( '' ) );
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}
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/**
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* Callback invoked once the stream has data to consume.
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*
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* @private
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*/
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function onReadable() {
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var chunk;
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while ( true ) {
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chunk = stream.read();
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if ( chunk === null ) {
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break;
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}
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if ( typeof chunk === 'string' ) {
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chunk = string2buffer( chunk );
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}
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data.push( chunk );
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len += chunk.length;
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}
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}
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/**
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* Callback invoked upon encountering a stream error.
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*
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* @private
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* @param {Error} error - error object
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*/
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function onError( error ) {
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clbk( error );
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}
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/**
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* Callback invoked after all data has been consumed.
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*
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* @private
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* @returns {void}
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*/
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function onEnd() {
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if ( enc ) {
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// Return a string...
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return clbk( null, data.join( '' ) );
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}
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// Return a buffer...
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clbk( null, Buffer.concat( data, len ) );
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}
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}
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// EXPORTS //
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module.exports = stdin;
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