Array flat() and flatMap()Baseline · Widely available
The flat() and flatMap() methods for arrays creates a new array such that each nested array item is concatenated into it.
Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Jan 15, 2020. Widely available since Jul 15, 2022.
Browser support
DesktopChrome
1–68Not supported
69+Supportedsince Sep 4, 2018
Current: 155Edge
12–18Not supported
79+Supportedsince Jan 15, 2020
Current: 154Firefox
1–61Not supported
62+Supportedsince Sep 5, 2018
Current: 157Safari
1–11.1Not supported
12+Supportedsince Sep 17, 2018
Current: 27MobileChrome Android
18–68Not supported
69+Supportedsince Sep 4, 2018
Current: 155Firefox Android
4–61Not supported
62+Supportedsince Sep 5, 2018
Current: 157Safari iOS
1–11.3Not supported
12+Supportedsince Sep 17, 2018
Current: 27How to use
This feature is Baseline widely available — use it freely, no fallback needed.
Example
Full syntax and examples are on MDN: flat.
Feature detection
JS · check before using
if ("flat" in Array || ("prototype" in Array && "flat" in Array.prototype)) {
// Array.flat is available
}Usage share
Sub-features
Support for each part of the feature (2). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| Array.flat | 69 | 79 | 62 | 12 | 69 | 62 | 12 |
| Array.flatMap | 69 | 79 | 62 | 12 | 69 | 62 | 12 |