Strings and template literals

Strings are sequences of characters. In JavaScript you can delimit them in three ways, all equivalent to the engine — but with one superpower reserved for backticks:

'single quotes';
'double quotes';
`backticks — template literals`;

Single and double quotes are interchangeable: use whichever lets you avoid escaping the other character in your text:

'L\'isola'; // the apostrophe needs to be escaped
"L'isola"; // here it doesn't
"He said \"hi\"";
'He said "hi"';

Escape characters

Inside any string you can insert "non-printable" characters with a backslash:

• \n — newline
• \t — tab
• \\ — a literal backslash
• \' / \" — literal single / double quote

console.log('line 1\nline 2');
// line 1
// line 2

Template literals: the syntax you want to use by default

Backticks unlock two things that are impossible with the other delimiters:

1. Multiline strings without escapes: literal newlines are allowed.
2. Interpolation: inside ${ … } you can place any JS expression and its value gets pasted into the result.

const nome = 'Anna';
const eta = 28;

const messaggio = `Ciao ${nome}, hai ${eta} anni.
Fra un anno ne avrai ${eta + 1}.`;

The expression inside ${ … } doesn't have to be a simple name: it can be anything that produces a value, including function calls and operators.

Concatenation with +

Historically strings were composed with +. It still works, and is useful in rare cases (e.g. building a string in multiple steps):

const a = 'Ciao';
const b = 'mondo';
a + ', ' + b + '!'; // 'Ciao, mondo!'

Try it

Review exercise