Add dynamic key, value pairs to JavaScript array or hash table

I'm trying to add a key value pair to an existing javascript associative array. The key needs to be a variable. This is for JSON encoding. I realize there are many plugins and frameworks for this, but I want a simple answer.

ary.push({name: val});

where ary is a new array, name is a variable containing the key, val is the value of this entry.

I'm doing this in a jQuery loop that iterates through form fields.

Solution 1:

In ES6...

In ES6, you can use a destructuring assignment;

ary.push({[name]: val});

However, given this is ES6 syntax, the usual caveats apply; this will not work in some browsers (noticably, IE and Edge 13)... although Babel will transpile this for you.

Without ES6 (legacy browser support)...

You need to define an object and use square bracket notation to set the property;

var obj = {};

obj[name] = val;

ary.push(obj);

If you get the urge to read into it more, see this article on the differences between square bracket and dot notation.

Solution 2:

var ary = [];

function pushToAry(name, val) {
   var obj = {};
   obj[name] = val;
   ary.push(obj);
}

pushToAry("myName", "myVal");

Having just fully read your question though, all you need is the following

$(your collection of form els).serializeArray();

Good old jQuery

Solution 3:

An "associative array" is really just an object. You don't use push, you just assign properties to the object:

ary[name] = val;