Question

I find myself making (potentially) more work for myself, by having to specify each dynamic key one line at a time.

What I am doing now to add additional keys to an existing object:

create_request[('title_' + id)] = field_data[0];
create_request[('field_' + id)] = field_data[1];

What I was hoping to be able to do is something like:

jQuery.extend({('title_' + id) : field_data[0], ('field_' + id) : field_data[1]});

Is there an easier way than what I am doing now (since what I was hoping would work doesn’t)? Or is this just a limitation of the language?

Edit for clarity:

Okay, so you can create an object in javascript like this:

{
 a : 1
}

But that assumes that a is the string value for the key. What if I wanted the key to be the value of a variable?

I could do:

the_object[variable] = 1

But what if I wanted to do more than one of these dynamic insertions into the object? Is there a convenient way to do that?

Answer 1

If I could change just one thing about JavaScript, it would be object literal syntax. I think the property names should be evaluated as expressions the same as the property values; I think the benefits of this would outway the nuisance of being forced to include quoted property names when using static names. But, if wishes were fishes…

Using the square-bracket notation is the only built-in way to set properties with dynamic names, but it is not difficult to create your own function that takes input very similar to the syntax you hoped to use:

extendObject(obj, props) {
   for (var i = 0; i < props.length; i+=2)
      obj[props[i]] = props[i+1];
}

extendObject(create_request, ['title_' + id, field_data[0], 'field_' + id, field_data[1]]);

By using an array rather than a plain object to hold the new property names and values you can use dynamic names.

(Note also that even with the square-bracket syntax in your question you’ve made it slightly more complicated than it needs to be by including redundant parentheses.)