Question

If I have an object defined as:

var myObj={};

Then, I update this object with:

myObj['fruit']=['apple', 'orange'];

Later, I would like to append "[banana, melon]" to myObj['fruit'], that’s update myObj to

['apple','orange','banana','melon']

what is the most elegant way to update ‘fruit’ attribute value of myObj in my case? That’s update array by appending a new array.

——–EDIT——-

I need a way to append array as one variable, not extract each element of the appended array and push. e.g. oldArray append with newArray = final array

Answer 1

JavaScript has a built in Array.push()

myObj["fruit"].push( 'banana', 'melon' );

There are a few ways to approach appending an array. First up, use apply() to call push with the array as individual arguments:

var toAppend = ['banana', 'melon'];
// note [].push is just getting the "push" function from an empty array
// the first argument to "apply" is the array you are pushing too, the
// second is the array containing items to append
[].push.apply( myObj["fruit"], toAppend );

Also, you could concat() the arrays, however concat doesn’t modify the original array so if you have other references they might get lost:

myObj["fruit"] = myObj["fruit"].concat( toAppend );