Strings

Strings in JavaScript are arrays of characters. You define them using single or double quotes, or backticks:

"Hi there";
"Hi there";

Bothe double quoted and single strings allow escape characters:

  "Hi \\n "there";

The choice of quote mark style is left up to you.

Concatenation

You can concatenate strings using the + character:

"Hello " + "There";

It is sometimes useful to compose a string from an array, like so:

["parts", "of", "a", "url"].join("/");
// returns 'parts/of/a/url'

Backtick Strings

Backtick strings allow newlines and embedded code:

const name = "dave"`
hi ${name}
How are you doing today?
`;

Backtick strings are extremely useful for a lot of things.

Strings as arrays

Strings act like arrays. Access a part of a string using the square brace syntax like so:

"Hello there"[0]; // returns "H"

Note that although strings look like arrays, they are not arrays, and don’t give you the full array API.

Handy functions

You can convert a string into an array using the split function:

"Hello".split("");
// ['H', 'e', 'l', 'l', 'o']

You can join the array back up again using the join function:

["H", "e", "l", "l", "o"].join("");
// "Hello"

If you want to reverse a string you can split it, reverse the array, then join them back together again:

"Hello".split("").reverse().join("");
// "olleH"

You can replace a value in a string using the replace function:

"Hello".replaceAll("l", "w").replaceAll("e", "a");
// "Hawwo"

You can also use a regular expression:

"Hello".replace(/l/g, "w");
// "Hewwo"