JavaScript add strings
last modified October 18, 2023
In this article we show how to concatenate strings in JavaScript.
In JavaScript, a string is an object used to represent and manipulate a sequence of characters.
There are several ways of adding strings in JavaScript:
- + operator
- concat method
- join method
- formatting strings
JavaScript add strings with + operator
The easiest way of concatenating strings is to use the + or the
+= operator. The + operator is used both for adding
numbers and strings; in programming we say that the operator is
overloaded.
let a = 'old'; let b = ' tree'; let c = a + b; console.log(c);
In the example, we add two strings with the + opeartor.
$ node add_string.js old tree
In the second example, we use the compound addition operator.
let msg = 'There are'; msg += ' three falcons'; msg += ' in the sky'; console.log(msg);
The example builds a message with the += operator.
$ node add_string2.js There are three falcons in the sky
JavaScript add strings with join
The join method creates and returns a new string by concatenating
all of the elements of an array.
let words = ['There', 'are', 'three', 'falcons', 'in', 'the', 'sky'];
let msg = words.join(' ');
console.log(msg);
The example forms a message by concatenating words of an array.
$ node joining.js There are three falcons in the sky
JavaScript add strings with concat
The concat method concatenates the string arguments to the calling
string and returns a new string.
Because the concat method is less efficient than the +
operator, it is recommended to use the latter instead.
let a = 'old';
let c = a.concat(' tree');
console.log(c);
The example concatenates two strings with the built-in concat
method.
JavaScript add strings with string formatting
We can build JavaScript strings with string formatting, which is essentially another form of string addition.
let w1 = 'two';
let w2 = 'eagles';
let msg = `There are ${w1} ${w2} in the sky`;
console.log(msg);
The example builds a message using template literals.
$ node formatting.js There are two eagles in the sky
Source
In this article we have presented several ways of concatenating strings in JavaScript.