JavaScript Concat
concat() joins one or more strings onto the end of the string it is called on and returns the combined result. In modern JavaScript the + operator or template literals do the same job more readably, but concat makes chaining explicit.
Syntax
str.concat(str1, str2, ...)Examples
| Input | Arguments | Output |
|---|---|---|
| "foo" | "bar" | "foobar" |
| "a" | "b", "c" | "abc" |
| ↳ concat accepts multiple arguments. | ||
When to use it
- Build a string from several parts in a pipeline.
Gotchas
- For readability, prefer `${a}${b}` template literals or a + b in everyday code.
Try it live
Type your input and see Concat transform it instantly.
Want to go further? Chain Concat with other functions in the visual Playground — pipe one output into the next and watch your data transform.