What does +_ operator mean in JavaScript ?

Last Updated : 06 Jan, 2023

Unary Operator: A unary operation contain only one operand. Here, the '+' unary plus operator converts its operand to Number type. While it also acts as an arithmetic operator with two operands which returns an addition result on calculation.

JavaScript Identifiers: Javascript Identifiers are used to name variables (and keywords, functions, and labels). In Javascript, the first character must be a letter, or an underscore ( _ ), or a dollar sign ( $ ) but not a digit and subsequent characters may be letters, digits, underscores, or dollar signs.
JavaScript +_ operator: It is a combination of the variable with the symbol underscore( _ ) and unary plus ( + ) operator, + operator converts the type of _ variable to Number type for further operation.

Example: The variable "_" with string type is stored in variable "r" with "number" type.

Input:

var _ = "1";
var r = +_;

Output:

typeof(r) will be number

Example 1: Conversion of String to Number

HTML

<body style="text-align:center">
    <div class="container">
        <h1 style="color:green">Geeks for Geeks</h1>

        <h3>
            Javascript Operator
        </h3>

        <p align="center">
            Type of variable(_) :
            <span id="gfg"></span> <br />
            Type of variable(a) :
            <span id="gfg1"></span>
        </p>

        <script type="text/javascript">
            GFG = function (_) {
                let b = typeof _;
                let a = +_;
                let c = typeof a;
            
                document.getElementById("gfg").innerHTML = b;
                document.getElementById("gfg1").innerHTML = c;
            };
            
            GFG("21");
        </script>
    </div>
</body>

Output:

Example 2: Performing arithmetic addition operations by converting them to number type.