Nullish coalescing operator (??) - JavaScript | MDN

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2026-07-24 09:59:41

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Text Highlight2026-07-24 13:20:41

Original Highlight Excerpt

"the right-hand side expression is not evaluated if the left-hand side proves to be neither null nor undefined"

Whisper Note

Wait, does that mean it short-circuits like && and ||? I never noticed.

Text Highlight2026-07-24 13:11:41

Original Highlight Excerpt

"the right-hand side expression is not evaluated if the left-hand side proves to be neither null nor undefined"

Whisper Note

So it's basically lazy evaluation, that's useful for expensive calls.

Text Highlight2026-07-24 10:17:41

Original Highlight Excerpt

"The nullish coalescing operator avoids this pitfall by only returning the second operand when the first one evaluates to either null or undefined"

Whisper Note

This saved my life when 0 was a valid value in a form field, not gonna lie.

Text Highlight2026-07-24 10:08:41

Original Highlight Excerpt

"The nullish coalescing operator avoids this pitfall by only returning the second operand when the first one evaluates to either null or undefined"

Whisper Note

But honestly, who ever trips on 0 being falsy? Just use || like a normal person.

Text Highlight2026-07-24 09:59:41

Original Highlight Excerpt

"The nullish coalescing operator avoids this pitfall by only returning the second operand when the first one evaluates to either null or undefined"

Whisper Note

Finally, no more accidentally using 0 or empty string when I meant null.

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