How to add an object in an array?

Question

I am trying to push object into an array

I have something like these

for(var i=0; i<test.length; i++){
    console.log(test[i])
    console.log(items[test[i]])
    productObj.push( { test[i] : items[test[i]]} );
}

both console.log show stuff but I have an error on the push(). The error is "Uncaught SyntaxError: Unexpected token ["

Can anyone help me about this weird issue? Thanks!

score 3 · Accepted Answer · answered Aug 18 '14 at 21:50

3

Object literal keys need to be constant. test[i] isn't going to work. You'll need to create an empty object and add the key/value pair:

var o = {};
o[ test[i] ] = items[test[i]];

productObj.push( o );

answered Aug 18 '14 at 21:50

Paul Roub

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score 2 · Answer 2 · answered Aug 18 '14 at 21:50

The keys in an object literal are not evaluated and must be valid identifiers.

You would get the same error just from the object literal: { test[i]: 1 }.

You can use the new keyword in conjunction with an anonymous function to create the object instead:

productObj.push( new function () { this[test[i]] = items[test[i]]; } );

If you find that the above is less readable, then you should create the object in advance:

var temp = {};
temp[test[i]] = items[test[i]];
productObj.push( temp );

score 1 · Answer 3 · answered Aug 18 '14 at 21:50

The key of an entry in the {} syntax for creating objects is not looked up as a variable, it must be a valid identifier. test[i] is not a valid identifier due to the brackets, and even if it was it would not get evaluated.

To create a key from test[i], you have to manually add it using the [] syntax.

var v = {};
v[test[i]] = ...

How to add an object in an array?

3 Answers3