Array.prototype without modifying the original array

Question

Array.prototype without modifying the original array

I want to create a new Array method without modifying the original array.

my_array.push('foo') //modifies my_array
my_array.slice(2) //returns a new array without modifying my_array

I would like to create a new Array.prototype method that returns an array without modifying the array it was called on. This way it would be possible:

//[define new method here] Array.prototype.add_foo = function() {...
var my_array = ['poo'];

my_array.add_foo(); //would return ['poo', 'foo'];
my_array; //would return ['poo'];

+3

javascript arrays

northamerican Aug 29. 14 at 2:43

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2 answers

my_array.concat('foo');

concat

does not modify the original array.

+3

benjaminadk June 24. 17 at 6:25 am

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spender · Accepted Answer · 2014-08-29T02:47:00+0000

Array.prototype.add_foo = function(){
    var ret = this.slice(0); //make a clone
    ret.push("foo"); //add the foo
    return ret; //return the modified clone
}

Array.prototype without modifying the original array

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