| | 14 | |
| | 15 | // Tests for equality any JavaScript type and structure without unexpected results. |
| | 16 | // Discussions and reference: http://philrathe.com/articles/equiv |
| | 17 | // Test suites: http://philrathe.com/tests/equiv |
| | 18 | // Author: Philippe Rathé <prathe@gmail.com> |
| | 19 | var equiv = function () { |
| | 20 | |
| | 21 | var innerEquiv; // the real equiv function |
| | 22 | var callers = []; // stack to decide between skip/abort functions |
| | 23 | |
| | 24 | // Determine what is o. |
| | 25 | function hoozit(o) { |
| | 26 | if (typeof o === "string") { |
| | 27 | return "string"; |
| | 28 | |
| | 29 | } else if (typeof o === "boolean") { |
| | 30 | return "boolean"; |
| | 31 | |
| | 32 | } else if (typeof o === "number") { |
| | 33 | |
| | 34 | if (isNaN(o)) { |
| | 35 | return "nan"; |
| | 36 | } else { |
| | 37 | return "number"; |
| | 38 | } |
| | 39 | |
| | 40 | } else if (typeof o === "undefined") { |
| | 41 | return "undefined"; |
| | 42 | |
| | 43 | // consider: typeof null === object |
| | 44 | } else if (o === null) { |
| | 45 | return "null"; |
| | 46 | |
| | 47 | // consider: typeof [] === object |
| | 48 | } else if (o instanceof Array) { |
| | 49 | return "array"; |
| | 50 | |
| | 51 | // consider: typeof new Date() === object |
| | 52 | } else if (o instanceof Date) { |
| | 53 | return "date"; |
| | 54 | |
| | 55 | // consider: /./ instanceof Object; |
| | 56 | // /./ instanceof RegExp; |
| | 57 | // typeof /./ === "function"; // => false in IE and Opera, |
| | 58 | // true in FF and Safari |
| | 59 | } else if (o instanceof RegExp) { |
| | 60 | return "regexp"; |
| | 61 | |
| | 62 | } else if (typeof o === "object") { |
| | 63 | return "object"; |
| | 64 | |
| | 65 | } else if (o instanceof Function) { |
| | 66 | return "function"; |
| | 67 | } |
| | 68 | } |
| | 69 | |
| | 70 | // Call the o related callback with the given arguments. |
| | 71 | function bindCallbacks(o, callbacks, args) { |
| | 72 | var prop = hoozit(o); |
| | 73 | if (prop) { |
| | 74 | if (hoozit(callbacks[prop]) === "function") { |
| | 75 | return callbacks[prop].apply(callbacks, args); |
| | 76 | } else { |
| | 77 | return callbacks[prop]; // or undefined |
| | 78 | } |
| | 79 | } |
| | 80 | } |
| | 81 | |
| | 82 | var callbacks = function () { |
| | 83 | |
| | 84 | // for string, boolean, number and null |
| | 85 | function useStrictEquality(b, a) { |
| | 86 | return a === b; |
| | 87 | } |
| | 88 | |
| | 89 | return { |
| | 90 | "string": useStrictEquality, |
| | 91 | "boolean": useStrictEquality, |
| | 92 | "number": useStrictEquality, |
| | 93 | "null": useStrictEquality, |
| | 94 | "undefined": useStrictEquality, |
| | 95 | |
| | 96 | "nan": function (b) { |
| | 97 | return isNaN(b); |
| | 98 | }, |
| | 99 | |
| | 100 | "date": function (b, a) { |
| | 101 | return hoozit(b) === "date" && a.valueOf() === b.valueOf(); |
| | 102 | }, |
| | 103 | |
| | 104 | "regexp": function (b, a) { |
| | 105 | return hoozit(b) === "regexp" && |
| | 106 | a.source === b.source && // the regex itself |
| | 107 | a.global === b.global && // and its modifers (gmi) ... |
| | 108 | a.ignoreCase === b.ignoreCase && |
| | 109 | a.multiline === b.multiline; |
| | 110 | }, |
| | 111 | |
| | 112 | // - skip when the property is a method of an instance (OOP) |
| | 113 | // - abort otherwise, |
| | 114 | // initial === would have catch identical references anyway |
| | 115 | "function": function () { |
| | 116 | var caller = callers[callers.length - 1]; |
| | 117 | return caller !== Object && |
| | 118 | typeof caller !== "undefined"; |
| | 119 | }, |
| | 120 | |
| | 121 | "array": function (b, a) { |
| | 122 | var i; |
| | 123 | var len; |
| | 124 | |
| | 125 | // b could be an object literal here |
| | 126 | if ( ! (hoozit(b) === "array")) { |
| | 127 | return false; |
| | 128 | } |
| | 129 | |
| | 130 | len = a.length; |
| | 131 | if (len !== b.length) { // safe and faster |
| | 132 | return false; |
| | 133 | } |
| | 134 | for (i = 0; i < len; i++) { |
| | 135 | if( ! innerEquiv(a[i], b[i])) { |
| | 136 | return false; |
| | 137 | } |
| | 138 | } |
| | 139 | return true; |
| | 140 | }, |
| | 141 | |
| | 142 | "object": function (b, a) { |
| | 143 | var i; |
| | 144 | var eq = true; // unless we can proove it |
| | 145 | var aProperties = [], bProperties = []; // collection of strings |
| | 146 | |
| | 147 | // comparing constructors is more strict than using instanceof |
| | 148 | if ( a.constructor !== b.constructor) { |
| | 149 | return false; |
| | 150 | } |
| | 151 | |
| | 152 | // stack constructor before traversing properties |
| | 153 | callers.push(a.constructor); |
| | 154 | |
| | 155 | for (i in a) { // be strict: don't ensures hasOwnProperty and go deep |
| | 156 | |
| | 157 | aProperties.push(i); // collect a's properties |
| | 158 | |
| | 159 | if ( ! innerEquiv(a[i], b[i])) { |
| | 160 | eq = false; |
| | 161 | } |
| | 162 | } |
| | 163 | |
| | 164 | callers.pop(); // unstack, we are done |
| | 165 | |
| | 166 | for (i in b) { |
| | 167 | bProperties.push(i); // collect b's properties |
| | 168 | } |
| | 169 | |
| | 170 | // Ensures identical properties name |
| | 171 | return eq && innerEquiv(aProperties.sort(), bProperties.sort()); |
| | 172 | } |
| | 173 | }; |
| | 174 | }(); |
| | 175 | |
| | 176 | innerEquiv = function () { // can take multiple arguments |
| | 177 | var args = Array.prototype.slice.apply(arguments); |
| | 178 | if (args.length < 2) { |
| | 179 | return true; // end transition |
| | 180 | } |
| | 181 | |
| | 182 | return (function (a, b) { |
| | 183 | if (a === b) { |
| | 184 | return true; // catch the most you can |
| | 185 | |
| | 186 | } else if (typeof a !== typeof b || a === null || b === null || typeof a === "undefined" || typeof b === "undefined") { |
| | 187 | return false; // don't lose time with error prone cases |
| | 188 | |
| | 189 | } else { |
| | 190 | return bindCallbacks(a, callbacks, [b, a]); |
| | 191 | } |
| | 192 | |
| | 193 | // apply transition with (1..n) arguments |
| | 194 | })(args[0], args[1]) && arguments.callee.apply(this, args.splice(1, args.length -1)); |
| | 195 | }; |
| | 196 | |
| | 197 | return innerEquiv; |
| | 198 | }(); // equiv |
| 387 | | // Test for equality any JavaScript type. |
| 388 | | // Discussions and reference: http://philrathe.com/articles/equiv |
| 389 | | // Test suites: http://philrathe.com/tests/equiv |
| 390 | | // Author: Philippe Rathé <prathe@gmail.com> |
| 391 | | |
| 392 | | // About passing arguments: |
| 393 | | // when < 2 : return true |
| 394 | | // when 2 : return true if 1st equals 2nd |
| 395 | | // when > 2 : return true 1st equals 2nd, and 2nd equals 3rd, |
| 396 | | // and 3rd equals 4th ... ans so on (by transition) |
| 397 | | // |
| 398 | | |
| 399 | | // Stack of constructors that enables us to skip or abort on functions value. |
| 400 | | var objectCallerConstructorStack = []; |
| 401 | | function equiv() { |
| 402 | | // we will need to use the array splice method, |
| 403 | | // so we need to convert arguments into a true array. |
| 404 | | var args = Array.prototype.slice.apply(arguments); |
| 405 | | var a, b; // compares a and b (1st and 2nd argument) |
| 406 | | var i; // for iterating over objects convenience |
| 407 | | var len; // for iterating array's length memoization |
| 408 | | // Memoized objects' properties. |
| 409 | | // Allow us to test for equivalence only in one way, |
| 410 | | // then to compare properties to make sure no one is missing. |
| 411 | | var aProperties, bProperties; |
| 412 | | |
| 413 | | |
| 414 | | if (args.length < 2) { |
| 415 | | return true; // nothing to compare together |
| 416 | | } |
| 417 | | |
| 418 | | a = args[0]; |
| 419 | | b = args[1]; |
| 420 | | |
| 421 | | return (function (a, b) { |
| 422 | | |
| 423 | | // Try to optimize the algo speed if ever both a and b are references |
| 424 | | // pointing to the same object (e..g. only for functions, arrays and objects) |
| 425 | | if (a === b) { |
| 426 | | return true; |
| 427 | | } |
| 428 | | |
| 429 | | // Must test for the null value before testing for the type of an object, |
| 430 | | // because null is also an object. Trapping null or undefined values here |
| 431 | | // is a good to avoid to much validations further in the code. |
| 432 | | if (a === null || b === null || typeof a === "undefined" || typeof b === "undefined") { |
| 433 | | return false; // Anyway (a === b) would have already caught it. |
| 434 | | } |
| 435 | | |
| 436 | | // Don't lose time and prevent further wrong type manipulation or unexpected results. |
| 437 | | if (typeof a !== typeof b) { |
| 438 | | return false; |
| 439 | | } |
| 440 | | |
| 441 | | // Must test if it's an array before testing for the type of an object, |
| 442 | | // because an array is also an object. |
| 443 | | if (a instanceof Array) { |
| 444 | | |
| 445 | | // Make sure b is also an array. |
| 446 | | // At this point b can be an object. |
| 447 | | // Prevent further arrays operation on object. |
| 448 | | if ( ! (b instanceof Array)) { |
| 449 | | return false; |
| 450 | | } |
| 451 | | |
| 452 | | len = a.length; |
| 453 | | if (len !== b.length) { // safe and faster |
| 454 | | return false; |
| 455 | | } |
| 456 | | for (i = 0; i < len; i++) { |
| 457 | | if( ! equiv(a[i], b[i])) { |
| 458 | | return false; |
| 459 | | } |
| 460 | | } |
| 461 | | return true; |
| 462 | | } |
| 463 | | |
| 464 | | // NOTE: |
| 465 | | // Must test if it's a date before testing if it is an object, |
| 466 | | // because a date is also an object. |
| 467 | | // We don't need to check if b is also an instance of Date because |
| 468 | | // the "different type check" sooner in the code would have caught it and |
| 469 | | // return false by evaluating ("object" !== "number") (or conversely) to true. |
| 470 | | if (a instanceof Date) { |
| 471 | | return a.valueOf() === b.valueOf(); |
| 472 | | } |
| 473 | | |
| 474 | | // NOTE: |
| 475 | | // Using toSource() to compare regexp only works in FF. It was working as well as the above. |
| 476 | | // Must verify the constructor of a regexp before verifying it is an object. |
| 477 | | // Notice those confusing true statements: |
| 478 | | // var a = /./; |
| 479 | | // a instanceof Object; // => true |
| 480 | | // a instanceof RegExp; // => true |
| 481 | | // typeof a === "function"; // => false in IE and Opera, true in FF and Safari |
| 482 | | // |
| 483 | | // There is 3 possible modifier for regular expressions (g, m and i) |
| 484 | | // The source property only returns the regular expression string without the modifier. |
| 485 | | if (a instanceof RegExp) { |
| 486 | | return b instanceof RegExp && |
| 487 | | a.source === b.source && |
| 488 | | a.global === b.global && |
| 489 | | a.ignoreCase === b.ignoreCase && |
| 490 | | a.multiline === b.multiline; |
| 491 | | } |
| 492 | | |
| 493 | | // typeof on some types returns sometimes unexpected type that we deals with. |
| 494 | | // We could have used instanceof instead of typeof but it comes with |
| 495 | | // other problems as mentioned above when testing for the RegExp constructor. |
| 496 | | // We explicitely don't use hasOwnProperty when iterating on the properties of |
| 497 | | // an object to allow a deeper equivalence (e.g. for instances particularly) |
| 498 | | if (typeof a === "object") { |
| 499 | | // Different constructors means a and b can't be equivalent instances. |
| 500 | | // We don't have any choice of comparing them in both ways because of inheritance |
| 501 | | // otherwise {} could be mistaken with [] |
| 502 | | // NOTE this: |
| 503 | | // var a = []; |
| 504 | | // a instanceof Array; // true |
| 505 | | // a instanceof Object; // true |
| 506 | | if ( a.constructor !== b.constructor) { |
| 507 | | return false; |
| 508 | | } |
| 509 | | |
| 510 | | // Stack constructors before iterating over its properties |
| 511 | | objectCallerConstructorStack.push(a.constructor); |
| 512 | | |
| 513 | | aProperties = []; |
| 514 | | bProperties = []; |
| 515 | | |
| 516 | | // NOTE: |
| 517 | | // We only need to compare propertie's equivalence in one way |
| 518 | | // and ensures that all properties of a and b are the same. |
| 519 | | |
| 520 | | // Verify a's properties with b's properties equivalence. |
| 521 | | // Stack a's properties |
| 522 | | |
| 523 | | for (i in a) { |
| 524 | | aProperties.push(i); |
| 525 | | if (!equiv(a[i], b[i])) { |
| 526 | | // Unstack current constructor when finished with the object |
| 527 | | objectCallerConstructorStack.pop(); |
| 528 | | return false; |
| 529 | | } |
| 530 | | } |
| 531 | | |
| 532 | | // Stack also b's properties |
| 533 | | for (i in b) { |
| 534 | | bProperties.push(i); |
| 535 | | } |
| 536 | | |
| 537 | | // Unstack current constructor when finished with the object |
| 538 | | objectCallerConstructorStack.pop(); |
| 539 | | |
| 540 | | // Ensures properties's name in both ways. |
| 541 | | // Must sort them because they may not be always in the same order! |
| 542 | | return equiv(aProperties.sort(), bProperties.sort()); |
| 543 | | } |
| 544 | | |
| 545 | | // NOTE: |
| 546 | | // Using the typeof operator will also catch a RegExp instance. |
| 547 | | // Take no risk. |
| 548 | | if (a instanceof Function) { |
| 549 | | // BEHAVIOR when comparing functions. |
| 550 | | // Being here means that a and b were were not the same references. |
| 551 | | // At this level, functions won't be compared at all. |
| 552 | | // - skip when they are properties of instances (not instantiates from the Object construtor) |
| 553 | | // - abort otherwise |
| 554 | | // |
| 555 | | // To Determine if a function is anonymous we use a regexp on the function sources. |
| 556 | | var currentObjectCallerConstructor = |
| 557 | | objectCallerConstructorStack[objectCallerConstructorStack.length - 1]; |
| 558 | | return currentObjectCallerConstructor !== Object && |
| 559 | | typeof currentObjectCallerConstructor !== "undefined"; |
| 560 | | } |
| 561 | | |
| 562 | | // NaN is a number in JavaScript. |
| 563 | | // Because this statement is false: 0/0 === 0/0, |
| 564 | | // we must use the isNaN function which is the only way to know a number is NaN. |
| 565 | | // Note that it isn't the case with the Infinity number, and that 1/0 === 2/0. |
| 566 | | if (typeof a === "number" && isNaN(a)) { |
| 567 | | return isNaN(b); |
| 568 | | } |
| 569 | | |
| 570 | | // Compares Number, String or Boolean |
| 571 | | // Because sooner we have already tried: |
| 572 | | // a === b (then return if it is the case) |
| 573 | | // and |
| 574 | | // typeof a !== typeof b (then return false if it is the case) |
| 575 | | // at this time a and b should be of the same type, but hold different values. |
| 576 | | // We can safely return false instead of returning a === b |
| 577 | | return false; |
| 578 | | |
| 579 | | }(a, b)) && equiv.apply(this, args.splice(1, args.length -1)); // apply transition with (1..n) arguments |
| 580 | | } |
| 581 | | |
