How to use variables in dot notation like square bracket notation

Question

I have been using square bracket notation in Javascript to create and call associative arrays.

In this example, I understand that square bracket notation allows you to use a variable to call a certain object in the array.

How would you do something like this in dot notation?

var item = {};
    item['1'] = 'pen';

var x = 1;

console.log(item[x]);  // console will show 'pen'

Answer 1

You can't use variables in dot notation (short of using eval, which you don't want to do). With dot notation the property name is essentially a constant.

myObj.propName
// is equivalent to
myObj["propName"]

Answer 2

You actually can now.

In this case you can use square brackets to use a variable for dot notation.

console.log(item.[x])

This is especially useful for use in Typescript.