Strings

Strings in JavaScript are sequences of text characters, contained within ', " or ` characters.

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We can use any of the three quotes (single, double or backtick) to define Strings, but we must start and end using the same character

let myName = "Martin";

let myName = "Martin";

let myName = `Martin`;

Special characters

We can include special characters in JavaScript Strings by escaping them using the \ character. \n adds a new line. \t adds a tab. \\ adds a \.

let myText = ‘This is one line\nThis is another’;

let myText = “\tThis is indented”;

let myText = “We can escape \” too”;

String concatentation

We can use the + operator to join Strings together

let myText = "Hello" + " " + "World!";

Template literals

Strings defined using ` characters (backticks) are template literals. These are special as we can embed expressions within them.

let numChildren = 2;
let tirednessAmount = "very";
let myText = `Martin has ${numChildren} children, which explains why Martin is ${tirednessAmount} tired`;

These expressions can be simple usage of variables, as above, or we can even carry out operations within our ${ ... } literals:

let bigOneAge = 5;
let thisYear = 2020;
let myText = `Martin's eldest child is ${bigOneAge} so Martin has been tired since ${thisYear - bigOneAge}`;

String Objects

Strings are actually a type of Object. Objects are more complicated data types in JavaScript that we aren’t going to worry about yet. All we need to know about them is that they have properties that tell us more about them, and methods which are functions that work on the Object itself…

Strings have a length property that tells us how long the String is:

let myText = "When, in disgrace with fortune and men’s eyes,\nI all alone beweep my outcast state,";
console.log(`myText length: ${myText.length}`);

Strings have a lot of different methods that we can use to alter, search, replace or do other things with:

let m = ‘The quick brown fox …’
console.log(m.toUpperCase());
console.log(m.replace(“fox”, “cat”));
console.log(m.slice(4, 8));

String demo

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