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Using Conditional Statements for Optional JavaScript Function Parameters
In JavaScript, it's common to use conditional statements to handle optional function parameters. Here's the example you provided:
<code class="javascript">function myFunc(requiredArg, optionalArg){ optionalArg = optionalArg || 'defaultValue'; // Do stuff }</code>
However, this approach can fail if the optional argument is passed but evaluates to false (e.g., empty string, 0). Here's a safer alternative:
<code class="javascript">if (typeof optionalArg === 'undefined') { optionalArg = 'default'; }</code>
This checks if the optional argument is undefined, in which case it assigns a default value.
Alternatively, you can use the conditional (ternary) operator:
<code class="javascript">optionalArg = (typeof optionalArg === 'undefined') ? 'default' : optionalArg;</code>
This idiom is more concise but conveys the same intent as the if statement.
Choose the idiom that best suits your preference and communicates the intended behavior clearly.
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