string-startswith.js (11976B)
1 /* 2 * Copyright (c) 2013 Mathias Bynens. All rights reserved. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in 12 * all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 19 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 20 * DEALINGS IN THE SOFTWARE. 21 */ 22 23 function assertThrows(fun, errorType) { 24 try { 25 fun(); 26 assertEq(true, false, "Expected error, but none was thrown"); 27 } catch (e) { 28 assertEq(e instanceof errorType, true, "Wrong error type thrown"); 29 } 30 } 31 32 Object.prototype[1] = 2; // try to break `arguments[1]` 33 34 assertEq(String.prototype.startsWith.length, 1); 35 assertEq(String.prototype.propertyIsEnumerable('startsWith'), false); 36 37 assertEq('undefined'.startsWith(), true); 38 assertEq('undefined'.startsWith(undefined), true); 39 assertEq('undefined'.startsWith(null), false); 40 assertEq('null'.startsWith(), false); 41 assertEq('null'.startsWith(undefined), false); 42 assertEq('null'.startsWith(null), true); 43 44 assertEq('abc'.startsWith(), false); 45 assertEq('abc'.startsWith(''), true); 46 assertEq('abc'.startsWith('\0'), false); 47 assertEq('abc'.startsWith('a'), true); 48 assertEq('abc'.startsWith('b'), false); 49 assertEq('abc'.startsWith('ab'), true); 50 assertEq('abc'.startsWith('bc'), false); 51 assertEq('abc'.startsWith('abc'), true); 52 assertEq('abc'.startsWith('bcd'), false); 53 assertEq('abc'.startsWith('abcd'), false); 54 assertEq('abc'.startsWith('bcde'), false); 55 56 assertEq('abc'.startsWith('', NaN), true); 57 assertEq('abc'.startsWith('\0', NaN), false); 58 assertEq('abc'.startsWith('a', NaN), true); 59 assertEq('abc'.startsWith('b', NaN), false); 60 assertEq('abc'.startsWith('ab', NaN), true); 61 assertEq('abc'.startsWith('bc', NaN), false); 62 assertEq('abc'.startsWith('abc', NaN), true); 63 assertEq('abc'.startsWith('bcd', NaN), false); 64 assertEq('abc'.startsWith('abcd', NaN), false); 65 assertEq('abc'.startsWith('bcde', NaN), false); 66 67 assertEq('abc'.startsWith('', false), true); 68 assertEq('abc'.startsWith('\0', false), false); 69 assertEq('abc'.startsWith('a', false), true); 70 assertEq('abc'.startsWith('b', false), false); 71 assertEq('abc'.startsWith('ab', false), true); 72 assertEq('abc'.startsWith('bc', false), false); 73 assertEq('abc'.startsWith('abc', false), true); 74 assertEq('abc'.startsWith('bcd', false), false); 75 assertEq('abc'.startsWith('abcd', false), false); 76 assertEq('abc'.startsWith('bcde', false), false); 77 78 assertEq('abc'.startsWith('', undefined), true); 79 assertEq('abc'.startsWith('\0', undefined), false); 80 assertEq('abc'.startsWith('a', undefined), true); 81 assertEq('abc'.startsWith('b', undefined), false); 82 assertEq('abc'.startsWith('ab', undefined), true); 83 assertEq('abc'.startsWith('bc', undefined), false); 84 assertEq('abc'.startsWith('abc', undefined), true); 85 assertEq('abc'.startsWith('bcd', undefined), false); 86 assertEq('abc'.startsWith('abcd', undefined), false); 87 assertEq('abc'.startsWith('bcde', undefined), false); 88 89 assertEq('abc'.startsWith('', null), true); 90 assertEq('abc'.startsWith('\0', null), false); 91 assertEq('abc'.startsWith('a', null), true); 92 assertEq('abc'.startsWith('b', null), false); 93 assertEq('abc'.startsWith('ab', null), true); 94 assertEq('abc'.startsWith('bc', null), false); 95 assertEq('abc'.startsWith('abc', null), true); 96 assertEq('abc'.startsWith('bcd', null), false); 97 assertEq('abc'.startsWith('abcd', null), false); 98 assertEq('abc'.startsWith('bcde', null), false); 99 100 assertEq('abc'.startsWith('', -Infinity), true); 101 assertEq('abc'.startsWith('\0', -Infinity), false); 102 assertEq('abc'.startsWith('a', -Infinity), true); 103 assertEq('abc'.startsWith('b', -Infinity), false); 104 assertEq('abc'.startsWith('ab', -Infinity), true); 105 assertEq('abc'.startsWith('bc', -Infinity), false); 106 assertEq('abc'.startsWith('abc', -Infinity), true); 107 assertEq('abc'.startsWith('bcd', -Infinity), false); 108 assertEq('abc'.startsWith('abcd', -Infinity), false); 109 assertEq('abc'.startsWith('bcde', -Infinity), false); 110 111 assertEq('abc'.startsWith('', -1), true); 112 assertEq('abc'.startsWith('\0', -1), false); 113 assertEq('abc'.startsWith('a', -1), true); 114 assertEq('abc'.startsWith('b', -1), false); 115 assertEq('abc'.startsWith('ab', -1), true); 116 assertEq('abc'.startsWith('bc', -1), false); 117 assertEq('abc'.startsWith('abc', -1), true); 118 assertEq('abc'.startsWith('bcd', -1), false); 119 assertEq('abc'.startsWith('abcd', -1), false); 120 assertEq('abc'.startsWith('bcde', -1), false); 121 122 assertEq('abc'.startsWith('', -0), true); 123 assertEq('abc'.startsWith('\0', -0), false); 124 assertEq('abc'.startsWith('a', -0), true); 125 assertEq('abc'.startsWith('b', -0), false); 126 assertEq('abc'.startsWith('ab', -0), true); 127 assertEq('abc'.startsWith('bc', -0), false); 128 assertEq('abc'.startsWith('abc', -0), true); 129 assertEq('abc'.startsWith('bcd', -0), false); 130 assertEq('abc'.startsWith('abcd', -0), false); 131 assertEq('abc'.startsWith('bcde', -0), false); 132 133 assertEq('abc'.startsWith('', +0), true); 134 assertEq('abc'.startsWith('\0', +0), false); 135 assertEq('abc'.startsWith('a', +0), true); 136 assertEq('abc'.startsWith('b', +0), false); 137 assertEq('abc'.startsWith('ab', +0), true); 138 assertEq('abc'.startsWith('bc', +0), false); 139 assertEq('abc'.startsWith('abc', +0), true); 140 assertEq('abc'.startsWith('bcd', +0), false); 141 assertEq('abc'.startsWith('abcd', +0), false); 142 assertEq('abc'.startsWith('bcde', +0), false); 143 144 assertEq('abc'.startsWith('', 1), true); 145 assertEq('abc'.startsWith('\0', 1), false); 146 assertEq('abc'.startsWith('a', 1), false); 147 assertEq('abc'.startsWith('b', 1), true); 148 assertEq('abc'.startsWith('ab', 1), false); 149 assertEq('abc'.startsWith('bc', 1), true); 150 assertEq('abc'.startsWith('abc', 1), false); 151 assertEq('abc'.startsWith('bcd', 1), false); 152 assertEq('abc'.startsWith('abcd', 1), false); 153 assertEq('abc'.startsWith('bcde', 1), false); 154 155 assertEq('abc'.startsWith('', +Infinity), true); 156 assertEq('abc'.startsWith('\0', +Infinity), false); 157 assertEq('abc'.startsWith('a', +Infinity), false); 158 assertEq('abc'.startsWith('b', +Infinity), false); 159 assertEq('abc'.startsWith('ab', +Infinity), false); 160 assertEq('abc'.startsWith('bc', +Infinity), false); 161 assertEq('abc'.startsWith('abc', +Infinity), false); 162 assertEq('abc'.startsWith('bcd', +Infinity), false); 163 assertEq('abc'.startsWith('abcd', +Infinity), false); 164 assertEq('abc'.startsWith('bcde', +Infinity), false); 165 166 assertEq('abc'.startsWith('', true), true); 167 assertEq('abc'.startsWith('\0', true), false); 168 assertEq('abc'.startsWith('a', true), false); 169 assertEq('abc'.startsWith('b', true), true); 170 assertEq('abc'.startsWith('ab', true), false); 171 assertEq('abc'.startsWith('bc', true), true); 172 assertEq('abc'.startsWith('abc', true), false); 173 assertEq('abc'.startsWith('bcd', true), false); 174 assertEq('abc'.startsWith('abcd', true), false); 175 assertEq('abc'.startsWith('bcde', true), false); 176 177 assertEq('abc'.startsWith('', 'x'), true); 178 assertEq('abc'.startsWith('\0', 'x'), false); 179 assertEq('abc'.startsWith('a', 'x'), true); 180 assertEq('abc'.startsWith('b', 'x'), false); 181 assertEq('abc'.startsWith('ab', 'x'), true); 182 assertEq('abc'.startsWith('bc', 'x'), false); 183 assertEq('abc'.startsWith('abc', 'x'), true); 184 assertEq('abc'.startsWith('bcd', 'x'), false); 185 assertEq('abc'.startsWith('abcd', 'x'), false); 186 assertEq('abc'.startsWith('bcde', 'x'), false); 187 188 assertEq('[a-z]+(bar)?'.startsWith('[a-z]+'), true); 189 assertThrows(function() { '[a-z]+(bar)?'.startsWith(/[a-z]+/); }, TypeError); 190 assertEq('[a-z]+(bar)?'.startsWith('(bar)?', 6), true); 191 assertThrows(function() { '[a-z]+(bar)?'.startsWith(/(bar)?/); }, TypeError); 192 assertThrows(function() { '[a-z]+/(bar)?/'.startsWith(/(bar)?/); }, TypeError); 193 var global = newGlobal(); 194 global.eval('this.re = /(bar)?/'); 195 assertThrows(function() { '[a-z]+/(bar)?/'.startsWith(global.re); }, TypeError); 196 197 // http://mathiasbynens.be/notes/javascript-unicode#poo-test 198 var string = 'I\xF1t\xEBrn\xE2ti\xF4n\xE0liz\xE6ti\xF8n\u2603\uD83D\uDCA9'; 199 assertEq(string.startsWith(''), true); 200 assertEq(string.startsWith('\xF1t\xEBr'), false); 201 assertEq(string.startsWith('\xF1t\xEBr', 1), true); 202 assertEq(string.startsWith('\xE0liz\xE6'), false); 203 assertEq(string.startsWith('\xE0liz\xE6', 11), true); 204 assertEq(string.startsWith('\xF8n\u2603\uD83D\uDCA9'), false); 205 assertEq(string.startsWith('\xF8n\u2603\uD83D\uDCA9', 18), true); 206 assertEq(string.startsWith('\u2603'), false); 207 assertEq(string.startsWith('\u2603', 20), true); 208 assertEq(string.startsWith('\uD83D\uDCA9'), false); 209 assertEq(string.startsWith('\uD83D\uDCA9', 21), true); 210 211 assertThrows(function() { String.prototype.startsWith.call(undefined); }, TypeError); 212 assertThrows(function() { String.prototype.startsWith.call(undefined, 'b'); }, TypeError); 213 assertThrows(function() { String.prototype.startsWith.call(undefined, 'b', 4); }, TypeError); 214 assertThrows(function() { String.prototype.startsWith.call(null); }, TypeError); 215 assertThrows(function() { String.prototype.startsWith.call(null, 'b'); }, TypeError); 216 assertThrows(function() { String.prototype.startsWith.call(null, 'b', 4); }, TypeError); 217 assertEq(String.prototype.startsWith.call(42, '2'), false); 218 assertEq(String.prototype.startsWith.call(42, '4'), true); 219 assertEq(String.prototype.startsWith.call(42, 'b', 4), false); 220 assertEq(String.prototype.startsWith.call(42, '2', 1), true); 221 assertEq(String.prototype.startsWith.call(42, '2', 4), false); 222 assertEq(String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 0), false); 223 assertEq(String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 1), true); 224 assertEq(String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 2), false); 225 assertThrows(function() { String.prototype.startsWith.call({ 'toString': function() { throw RangeError(); } }, /./); }, RangeError); 226 assertThrows(function() { String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, /./); }, TypeError); 227 228 assertThrows(function() { String.prototype.startsWith.apply(undefined); }, TypeError); 229 assertThrows(function() { String.prototype.startsWith.apply(undefined, ['b']); }, TypeError); 230 assertThrows(function() { String.prototype.startsWith.apply(undefined, ['b', 4]); }, TypeError); 231 assertThrows(function() { String.prototype.startsWith.apply(null); }, TypeError); 232 assertThrows(function() { String.prototype.startsWith.apply(null, ['b']); }, TypeError); 233 assertThrows(function() { String.prototype.startsWith.apply(null, ['b', 4]); }, TypeError); 234 assertEq(String.prototype.startsWith.apply(42, ['2']), false); 235 assertEq(String.prototype.startsWith.apply(42, ['4']), true); 236 assertEq(String.prototype.startsWith.apply(42, ['b', 4]), false); 237 assertEq(String.prototype.startsWith.apply(42, ['2', 1]), true); 238 assertEq(String.prototype.startsWith.apply(42, ['2', 4]), false); 239 assertEq(String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 0]), false); 240 assertEq(String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 1]), true); 241 assertEq(String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 2]), false); 242 assertThrows(function() { String.prototype.startsWith.apply({ 'toString': function() { throw RangeError(); } }, [/./]); }, RangeError); 243 assertThrows(function() { String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, [/./]); }, TypeError);