The concat() method of String values concatenates
the string arguments to this string and returns a new string.
Syntax
concat()
concat(str1)
concat(str1, str2)
concat(str1, str2, /* …, */ strN)
Parameters
str1, …,strN- : One or more strings to concatenate to
str.
- : One or more strings to concatenate to
Return value
A new string containing the combined text of the strings provided.
Description
The concat() function concatenates the string arguments to the calling
string and returns a new string. Changes to the original string or the returned string
don't affect the other.
If the arguments are not of the type string, they are converted to string values before concatenating.
The concat() method is very similar to the addition/string concatenation operators (+, +=), except that concat() coerces its arguments directly to strings, while addition coerces its operands to primitives first. For more information, see the reference page for the + operator.
Examples
Using concat()
The following example combines strings into a new string.
const hello = "Hello, ";
console.log(hello.concat("Kevin", ". Have a nice day."));
// Hello, Kevin. Have a nice day.
const greetList = ["Hello", " ", "Venkat", "!"];
"".concat(...greetList); // "Hello Venkat!"
"".concat({}); // "[object Object]"
"".concat([]); // ""
"".concat(null); // "null"
"".concat(true); // "true"
"".concat(4, 5); // "45"