Why Use a Plus Sign ( ) Before a JavaScript Function to Invoke It?

Function Invocation Using unary Operator

The practice of using a plus sign ( ) in front of a function expression in JavaScript may seem puzzling. Let's delve into its significance.

Essence of the Plus Sign

The operator compels the JavaScript parser to interpret the subsequent code as an expression. This technique is commonly employed with immediately invoked function expressions (IIFEs).

Purpose of IIFEs

IIFEs are convenient for encapsulating code within a function and invoking it immediately upon creation. Without the sign, the parser might treat the function expression as a declaration, which requires a name.

Syntax Variations

While the operator is a viable option, it's not the only one. Other unary operators like -, !, and ~ can also be used in place of . Alternatively, parentheses can be employed to achieve the same effect.

Correct Usages

Here are some examples of properly formed IIFEs with various operators:

+function() {
  console.log("Something.");
}();

-function() { 
  console.log("Something.");
}();

(function() { 
  console.log("Something.");
})();

In all these cases, the function expression is evaluated immediately due to its placement within parentheses or the use of a unary operator. This allows for code encapsulation and immediate execution upon creation.

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