JavaScript String concat() Method (original) (raw)
Last Updated : 29 Aug, 2024
The **concat() method in JavaScript join or concatenate two or more strings together. It does not change the existing strings and returns a new string. This method efficiently combines multiple strings into one, ensuring the original strings remain unchanged.
**Syntax
str1.concat(str2, str3, str4,......, strN)
**Parameters
- **str1, str2, …, strN: This method accepts the string paramters that need to be joined together. The number of arguments to this function is equal to the number of strings to be joined together.
**Note: If the parameters are not of String type, then first it converted to string before concatenating the strings.
**Return value
Returns a **new string that is the **combination of all the different strings passed to it as the argument.
**Example 1: Join Two Strings with concat() Method
The string “str” is initialized with the value “Welcome”. Then concat() method is used on str to combine it with “Geeks”.
JavaScript `
// JavaScript String concat() method // to merge strings together
// First string let str = "Welcome";
// Joining the strings together let concatStr = str.concat(" Geeks");
console.log(concatStr);
`
**Example 2: Concatenating Multiple Strings with concat() Method
The concatenates strings str1, str2, and str3 together. The result1 combines them without spaces, while result2 concatenates them with spaces.
JavaScript `
let str1 = 'Geeks' let str2 = 'For' let str3 = 'Geeks'
// Concating all the strings together without spaces let result1 = str1.concat(str2, str3) console.log('Result without spaces: ' + result1)
// Concating all the strings together with spaces let result2 = str1.concat(' ', str2, ' ', str3) console.log('Result with spaces: ' + result2)
`
Output
Result without spaces: GeeksForGeeks Result with spaces: Geeks For Geeks
Eample 3: Concatenate with Empty Strings
You can use the concat() method with empty strings to control the formatting or add spaces dynamically
JavaScript `
const str1 = "Hello"; const str2 = "";
const str = str1.concat(str2);
console.log(str);
`
We have a complete list of Javascript string methods, to check those please go through this Javascript String Complete reference article.