time-to-botec

Benchmark sampling in different programming languages
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main.js (3580B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2021 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 isNonNegativeInteger = require( '@stdlib/assert/is-nonnegative-integer' ).isPrimitive;
     25 var numGraphemeClusters = require( './../../num-grapheme-clusters' );
     26 var nextGraphemeClusterBreak = require( './../../next-grapheme-cluster-break' );
     27 var format = require( './../../format' );
     28 var round = require( '@stdlib/math/base/special/round' );
     29 var floor = require( '@stdlib/math/base/special/floor' );
     30 
     31 
     32 // MAIN //
     33 
     34 /**
     35 * Truncates a string in the middle to a specified length.
     36 *
     37 * @param {string} str - input string
     38 * @param {integer} len - output string length (including sequence)
     39 * @param {string} [seq='...'] - custom replacement sequence
     40 * @throws {TypeError} first argument must be a string
     41 * @throws {TypeError} second argument must be a nonnegative integer
     42 * @throws {TypeError} third argument must be a string
     43 * @returns {string} truncated string
     44 *
     45 * @example
     46 * var str = 'beep boop';
     47 * var out = truncateMiddle( str, 5 );
     48 * // returns 'b...p'
     49 *
     50 * @example
     51 * var str = 'beep boop';
     52 * var out = truncateMiddle( str, 5, '>>>' );
     53 * // returns 'b>>>p'
     54 *
     55 * @example
     56 * var str = 'beep boop';
     57 * var out = truncateMiddle( str, 10 );
     58 * // returns 'beep boop'
     59 *
     60 * @example
     61 * var str = 'beep boop';
     62 * var out = truncateMiddle( str, 0 );
     63 * // returns ''
     64 *
     65 * @example
     66 * var str = 'beep boop';
     67 * var out = truncateMiddle( str, 2 );
     68 * // returns '..'
     69 *
     70 * @example
     71 * var str = '🐺 Wolf Brothers 🐺';
     72 * var out = truncateMiddle( str, 7 );
     73 * // returns '🐺 ... 🐺'
     74 */
     75 function truncateMiddle( str, len, seq ) {
     76 	var seqLength;
     77 	var fromIndex;
     78 	var strLength;
     79 	var seqStart;
     80 	var nVisual;
     81 	var seqEnd;
     82 	var idx2;
     83 	var idx1;
     84 	if ( !isString( str ) ) {
     85 		throw new TypeError( format( 'invalid argument. First argument must be a string. Value: `%s`.', str ) );
     86 	}
     87 	if ( !isNonNegativeInteger( len ) ) {
     88 		throw new TypeError( format( 'invalid argument. Second argument must be a nonnegative integer. Value: `%s`.', len ) );
     89 	}
     90 	if ( arguments.length > 2 ) {
     91 		if ( !isString( seq ) ) {
     92 			throw new TypeError( format( 'invalid argument. Third argument must be a string. Value: `%s`.', seq ) );
     93 		}
     94 	}
     95 	seq = seq || '...';
     96 	seqLength = numGraphemeClusters( seq );
     97 	strLength = numGraphemeClusters( str );
     98 	fromIndex = 0;
     99 	if ( len > strLength ) {
    100 		return str;
    101 	}
    102 	if ( len - seqLength < 0 ) {
    103 		return seq.slice( 0, len );
    104 	}
    105 	seqStart = round( ( len - seqLength ) / 2 );
    106 	seqEnd = strLength - floor( ( len - seqLength ) / 2 );
    107 	nVisual = 0;
    108 	while ( nVisual < seqStart ) {
    109 		idx1 = nextGraphemeClusterBreak( str, fromIndex );
    110 		fromIndex = idx1;
    111 		nVisual += 1;
    112 	}
    113 	idx2 = idx1;
    114 	while ( idx2 > 0 ) {
    115 		idx2 = nextGraphemeClusterBreak( str, fromIndex );
    116 		if ( idx2 >= seqEnd + fromIndex - nVisual ) {
    117 			break;
    118 		}
    119 		fromIndex = idx2;
    120 		nVisual += 1;
    121 	}
    122 	return str.substring( 0, idx1 ) + seq + str.substring( idx2 );
    123 }
    124 
    125 
    126 // EXPORTS //
    127 
    128 module.exports = truncateMiddle;