Declaring variables in ES6

We don’t use the var keyword in ES6 anymore to declare variables:

var name = 'John'

Instead we have the “let” and “const” keywords for this purpose. With “let” we declare variables whose value can change over time:

let age = 30

…whereas const indicates a variable whose value is not expected to change:

const name = 'John'

We cannot reassign the name variable after this point:

name = 'Bill'

…will result in an error:

TypeError: Assignment to constant variable.

Constant variables must also be given a value immediately. The following is invalid:

const name
name = 'John'

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