How to Reliably Handle Optional Parameters in JavaScript?

Handling Optional Parameters in JavaScript: An Improved Approach

In JavaScript, optional function parameters are commonly handled using the || operator, as demonstrated below:

function myFunc(requiredArg, optionalArg) {
  optionalArg = optionalArg || 'defaultValue';

  // Do stuff
}

However, this approach may fail if optionalArg is passed but evaluates to false. To address this, consider the following improved methods:

1. Using if Statement:

if (typeof optionalArg === 'undefined') {
  optionalArg = 'default';
}

This checks if optionalArg is undefined and only assigns the default value if it is.

2. Using Ternary Operator:

optionalArg = (typeof optionalArg === 'undefined') ? 'default' : optionalArg;

This is a compact alternative to the if statement that achieves the same result.

By adopting these practices, you can ensure more robust and accurate handling of optional parameters in your JavaScript code.

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