js比较两个单独的数组或对象是否相等的实例代码

所谓js的中的传值,其实也就是说5种基本数据类型(null,undefind,boolean,number,string)

传引用也就是说的那个引用数据类型,(array和object)

基本数据类型的值不可变,而引用数据类型的值是可变的

所以当你比较数组和对象时,都是false;除非你是克隆的原份数据

即: var a = { name: "李四" }; var b = a;

大家通常称对象为引用类型,以此来和基本类型进行区分; 而对象值都是引用,所以的对象的比较也叫引用的比较,当且当他们都指向同一个引用时,即都引用的同一个基对象时,它们才相等.

1.比较两个单独的数组是否相等

JSON.stringify(a1) == JSON.stringify(a2)

或

a1.toString() == a2.toString()

要判断2个数组是否相同，把数组转换成字符串进行比较。

如果要比较两个数组的元素是否相等，则：

JSON.stringify([1,2,3].sort()) === JSON.stringify([3,2,1].sort());

或

[1,2,3].sort().toString() === [3,2,1].sort().toString();

判断2个数组是否相同，首先要把数组进行排序，然后转换成字符串进行比较。

2.比较两个单独的对象是否相等

let cmp = ( x, y ) => {// If both x and y are null or undefined and exactly the same if ( x === y ) {  return true; }// If they are not strictly equal, they both need to be Objects if ( ! ( x instanceof Object ) || ! ( y instanceof Object ) ) {  return false; }//They must have the exact same prototype chain,the closest we can do is//test the constructor. if ( x.constructor !== y.constructor ) {  return false; } for ( var p in x ) {  //Inherited properties were tested using x.constructor === y.constructor  if ( x.hasOwnProperty( p ) ) {  // Allows comparing x[ p ] and y[ p ] when set to undefined  if ( ! y.hasOwnProperty( p ) ) {   return false;  }  // If they have the same strict value or identity then they are equal  if ( x[ p ] === y[ p ] ) {   continue;  }  // Numbers, Strings, Functions, Booleans must be strictly equal  if ( typeof( x[ p ] ) !== "object" ) {   return false;  }  // Objects and Arrays must be tested recursively  if ( ! Object.equals( x[ p ], y[ p ] ) ) {   return false;  }  } } for ( p in y ) {  // allows x[ p ] to be set to undefined  if ( y.hasOwnProperty( p ) && ! x.hasOwnProperty( p ) ) {  return false;  } } return true;};

下面是StackOverflow大神封装的方法，可以学习一下：

1.比较数组

// Warn if overriding existing methodif(Array.prototype.equals) console.warn("Overriding existing Array.prototype.equals. Possible causes: New API defines the method, there's a framework conflict or you've got double inclusions in your code.");// attach the .equals method to Array's prototype to call it on any arrayArray.prototype.equals = function (array) { // if the other array is a falsy value, return if (!array)  return false; // compare lengths - can save a lot of time  if (this.length != array.length)  return false; for (var i = 0, l = this.length; i < l; i++) {  // Check if we have nested arrays  if (this[i] instanceof Array && array[i] instanceof Array) {   // recurse into the nested arrays   if (!this[i].equals(array[i]))    return false;    }     else if (this[i] != array[i]) {    // Warning - two different object instances will never be equal: {x:20} != {x:20}   return false;   }    }   return true;}// Hide method from for-in loopsObject.defineProperty(Array.prototype, "equals", {enumerable: false});