Do JavaScript Functions Always Return a Value?

JavaScript Function Return Value

While commenting functions in NetBeans, you noticed that it adds @returns {undefined} even when the function doesn't have an explicit return statement. Is it mandatory for JavaScript functions to return a value?

Answer:

Technically, the answer is yes. JavaScript functions must return something to notify the JS engine that the function has completed its execution. The default return value for functions without an explicit return statement is undefined.

Importance of Return Value

Even if you don't explicitly return a value, the return value still serves a crucial purpose. The JS engine uses it to determine when the function has finished and can jump to the next operation, such as calling event handlers.

Handling Undefined Return Values

In JavaScript, you can ignore the return value of a function. This is common practice, especially in situations like this:

<code class="javascript">(function() {
  console.log('This IIFE will return undefined, but we don't care');
})();</code>

Implication for NetBeans Commentary

Based on the above explanation, NetBeans' default commenting scheme is accurate. It suggests that every JavaScript function returns a value, explicitly or implicitly.

Conclusion:

While JavaScript functions don't require explicit return statements, they always return something to facilitate engine execution. The default return value for functions without explicit returns is undefined. It's best to follow NetBeans' suggestion and leave the @returns {undefined} commentary in place, even if the function doesn't seem to return anything.

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