time-to-botec

Benchmark sampling in different programming languages
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async.js (3018B)

      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 isString = require( '@stdlib/assert/is-string' ).isPrimitive;
     24 var isObject = require( '@stdlib/assert/is-plain-object' );
     25 var isFunction = require( '@stdlib/assert/is-function' );
     26 var readFile = require( './../../read-file' );
     27 var removeBOM = require( '@stdlib/string/remove-utf8-bom' );
     28 var parseJSON = require( '@stdlib/utils/parse-json' );
     29 var instanceOf = require( '@stdlib/assert/instance-of' );
     30 
     31 
     32 // MAIN //
     33 
     34 /**
     35 * Asynchronously reads a file as JSON.
     36 *
     37 * @param {(string|Buffer|integer)} file - file path or file descriptor
     38 * @param {(Options|string)} [options] - options
     39 * @param {(string|null)} [options.encoding] - file encoding
     40 * @param {string} [options.flag] - file status flag
     41 * @param {Function} [options.reviver] - JSON reviver
     42 * @param {Callback} clbk - callback
     43 * @throws {TypeError} options argument must be either a string or an object
     44 * @throws {TypeError} callback argument must be a function
     45 *
     46 * @example
     47 * var resolve = require( 'path' ).resolve;
     48 *
     49 * readJSON( resolve( __dirname, '..', 'package.json' ), onJSON );
     50 *
     51 * function onJSON( error, data ) {
     52 *     if ( error ) {
     53 *         throw error;
     54 *     }
     55 *     console.dir( data );
     56 * }
     57 */
     58 function readJSON( file, options, clbk ) {
     59 	var opts;
     60 	var done;
     61 	if ( arguments.length < 3 ) {
     62 		opts = {};
     63 		done = options;
     64 	} else {
     65 		if ( isString( options ) ) {
     66 			opts = {
     67 				'encoding': options
     68 			};
     69 		} else {
     70 			if ( !isObject( options ) ) {
     71 				throw new TypeError( 'invalid argument. Options argument must be either a string or an object. Value: `' + options + '`.' );
     72 			}
     73 			opts = options;
     74 		}
     75 		done = clbk;
     76 	}
     77 	if ( !isFunction( done ) ) {
     78 		throw new TypeError( 'invalid argument. Callback argument must be a function. Value: `' + done + '`.' );
     79 	}
     80 	readFile( file, opts, onRead );
     81 
     82 	/**
     83 	* Callback invoked upon reading a file.
     84 	*
     85 	* @private
     86 	* @param {(Error|null)} error - error object
     87 	* @param {(Buffer|string)} file - file contents
     88 	* @returns {void}
     89 	*/
     90 	function onRead( error, file ) {
     91 		if ( error ) {
     92 			return done( error );
     93 		}
     94 		file = file.toString();
     95 		if ( opts.encoding === 'utf8' ) {
     96 			file = removeBOM( file );
     97 		}
     98 		if ( opts.reviver ) {
     99 			file = parseJSON( file, opts.reviver );
    100 		} else {
    101 			file = parseJSON( file );
    102 		}
    103 		if ( instanceOf( file, Error ) ) {
    104 			return done( file );
    105 		}
    106 		done( null, file );
    107 	}
    108 }
    109 
    110 
    111 // EXPORTS //
    112 
    113 module.exports = readJSON;