JavaScript String concat()

In this tutorial, we will learn about the JavaScript String concat() method with the help of examples.

The concat() method concatenates given arguments to the given string.

Example

let emptyString = "";


// joint arguments string
let joinedString = emptyString.concat("JavaScript", " is", " fun.");

console.log(joinedString);

// Output: JavaScript is fun.

concat() Syntax

The syntax of the concat() method is:

str.concat(str1, ..., strN)

Here, str is a string.

concat() Parameters

The concat() method takes in an arbitrary number of strings to concatenate to str.

concat() Return Value

  • Returns a new string containing the combined text of the strings provided.

Note: The assignment operators like + and += are strongly recommended over the concat() method.

Example: Using concat() method

console.log("".concat({})); // [object Object]

console.log("".concat(null)); // null
console.log("".concat(true)); // true

console.log("".concat(4, 5)); // 45


let str1 = "Hello";
let str2 = "World";


// concatenating two strings
let newStr = str1.concat(", ", str2, "!");

console.log(newStr); // Hello, World!

Output

[object Object]
null
true
45
Hello, World!

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