JavaScript method to compare whether two objects are equal_javascript skills

The example in this article describes the method of comparing two objects for equality in JavaScript. Share it with everyone 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 are equal (arrays, sequences, dictionaries). But there is no relevant implementation in the JavaScript language. This js code compares js objects in various aspects to determine whether 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; 
};

Use:

objA={ 
 a:'123', 
 b:'456' 
}; 
objB={ 
 a:'123', 
 b:'000' 
}; 
var isEqual= cmp(objA, objB); 
 console.log(isEqual);  // false 不相同

I hope this article will be helpful to everyone’s JavaScript programming design.