JavaScript compares two methods for equality. javascript is equal.

Source: Internet
Author: User
Tags hasownproperty

JavaScript compares two methods for equality. javascript is equal.

This article describes how JavaScript compares two objects. Share it with you for your reference. The details are as follows:

In Python, you can use the cmp () built-in function to compare whether the data contained in two objects is equal (arrays, sequences, and dictionaries ). However, there is no relevant implementation in javascript. This js Code compares JavaScript objects to determine whether the two objects are equal.

cmp = function( 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; };

Usage:

ObjA = {a: '000000', B: '000000'}; objB = {a: '000000', B: '000'}; var isEqual = cmp (objA, objB); console. log (isEqual); // false is different

I hope this article will help you design javascript programs.

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