What does +_ operator mean in JavaScript ?

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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:

+_ operator in JavaScript

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

HTML

<body style="text-align:center"> 
    <div class="container"> 
        <h1 style="color:green"> 
            zambiatek 
        </h1> 
  
        <h3> 
            Addition Operation 
        </h3> 
  
        <p align="center"> 
            Value variable(_) : 
            <span id="gfg"></span> <br /> 
            Value of variable($) : 
            <span id="gfg1"></span> <br /> 
            Value of variable(Sum) : 
            <span id="gfg2"></span> 
        </p> 
  
        <script type="text/javascript"> 
            GFG = function (_, $) { 
                let c = +_ + +$; 
                let a = +_; 
                let b = +$; 
              
                document.getElementById("gfg").innerHTML = a; 
                document.getElementById("gfg1").innerHTML = b; 
                document.getElementById("gfg2").innerHTML = c; 
            }; 
              
            GFG("21", "45"); 
        </script> 
    </div> 
</body>