String.prototype.repeat(count) returns a new string made by concatenating the original text count times. It never mutates the original string.
Pass the required arguments shown below. Check return values and browser support before you rely on the result.
Call string.repeat. Start with this line.
str.repeat(count)| Call | What it does |
|---|---|
str.repeat(count) | Primary signature. |
string.repeat(...) | Call with the arguments your case needs. |
Built into JavaScript. Call repeat(...) on a string (or String instance) — no import required.
str.repeat(count)| Parameter | Description |
|---|---|
| count | Required. How many copies; must be ≥ 0 and finite |
| Return Value | Description |
|---|---|
| * | The value returned by string.repeat(). |
repeat()Concatenate a phrase several times inside a sentence.
const mood = "Happy! ";
console.log(`I feel ${mood.repeat(3)}`);
// I feel Happy! Happy! Happy! mood is "Happy! " (note the trailing space).mood.repeat(3) concatenates that unit back-to-back."I feel ".mood is still a single "Happy! ".0 yields empty; decimals truncate toward zero.
console.log(JSON.stringify("abc".repeat(0))); // ""
console.log("abc".repeat(1)); // "abc"
console.log("abc".repeat(2)); // "abcabc"
console.log("abc".repeat(3.5)); // "abcabcabc"repeat(0) returns "" — valid, no throw.3.5 becomes 3 before repeating.JSON.stringify makes "" visible in the console.Build separators and simple indent without a loop.
console.log("-".repeat(20));
// --------------------
const indent = " ".repeat(2);
console.log(indent + "nested item");
// nested item
console.log("*".repeat(5) + " STAR " + "*".repeat(5));
// ***** STAR *****"-".repeat(20) builds a divider of length 20.Array(n).fill(str).join(sep) — repeat itself does not insert gaps.String.prototype.repeat() is part of ES2015 and is Baseline Widely available across modern browsers.
Supported in Chrome 41+, Firefox 24+, Safari 9+, Edge 12+, and Node.js 4+. Not available in Internet Explorer without a polyfill.
Bottom line: Safe for modern web apps and current Node LTS releases. Feature-detect with if ("repeat" in String.prototype) or use a small polyfill for very old targets.
Learn how to replace the first match of a string or regular expression.
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