A shorthand for adding to a number or string with vanilla JS
Let’s say you had a string with a simple message on it.
var greeting = 'Hello, world!';
You want to add, “How are you today?” to the end of it. You might do something like this.
greeting = greeting + ' How are you today?';
That totally works (here’s a demo), but in JavaScript, there’s a shorthand you can use: +=
.
This adds whatever string you place after it to the existing string. Here’s that same task written with +=
instead.
greeting += ' How are you today?';
Here’s a working demo of this technique in action.
You can also use this approach with numbers.
var num = 100;
// num now equals 142
num += 42;
You can also use it to subtract values from numbers.
// num now equals 122
num -= 20;