如何扩展javascript中的array.push（），以便在调用push方法之后，元素不应被推入数组中？

Question

Example:

var animals = ['pigs', 'goats', 'sheep'];

console.log(animals.push('cows'));
// expected output: 4

console.log(animals);
// expected output: Array ["pigs", "goats", "sheep", "cows"]

animals.push('chickens');

//I want output such that, when i will push 'chickens' it should not get

pushed into the array.
console.log(animals);
// expected output: Array ["pigs", "goats", "sheep", "cows"]

Answer 1

my requirement is like that when i will call push method it should print "hii" but should not push any element

Not a good idea , but you can always override the existing push function by doing

Array.prototype.push = function(){ console.log("hii") };

Demo

 var arr = [1]; console.log(1,arr); //[1] Array.prototype.push = function(){console.log("hii") }; arr.push(2); //hii console.log(2,arr); //hii //[1] 

Note

• You'll notice that push method is being called (internally) when the array is initialized and when its value is printed on console .

Answer 2

From your situation the problem should me somewhere else because if you would modify native function, libraries that use it may start to return some weird values. but if you really want to do this, I suggest you wrap .push function with your own one using Array.prototype. You can read more about this https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype