slice(), substring(), substr()

Syntax

str.slice(start, end)
str.substring(start, end)

Examples

const text = "Hello World";

console.log(text.slice(0, 5));  // "Hello"
console.log(text.slice(6));     // "World"
console.log(text.slice(-5));    // "World" - last 5 characters

const text = "Hello World";

console.log(text.substring(0, 5)); // "Hello" - same as slice() here
console.log(text.substring(-3));   // "Hello World" - negative treated as 0!
console.log(text.substring(5, 0)); // "Hello" - swaps arguments if start > end

Best practices

• Prefer slice() over substring() and substr() - it has more predictable, useful behavior with negative indices and no deprecated status
• Avoid substr() entirely in new code - it is deprecated, even though many browsers still support it
• Remember all three treat the end index as exclusive - slice(0, 5) gets characters at indices 0 through 4
• Use negative indices with slice() to extract from the end without manually calculating string.length - n

At a glance

Purpose

Application logic and interaction

File extension

.js · .mjs

Runs in

Browsers and JavaScript runtimes

Usually used with

HTML, CSS and Web APIs

Specifications & further reading

• ECMAScript specification

Related JavaScript documentation