JavaScript Nullish Coalescing
An introduction to this feature of JavaScript: nullish coalescing
A powerful operator available in JavaScript is the nullish coalescing operator: ??.
Have you ever used || to set a default value if a variable was null or undefined?
For example, like this:
const myColor = color || 'red'Well, nullish coalescing is going to replace || in there:
const myColor = color ?? 'red'Why is this operator useful?
Well, there is a whole range of bugs that hide underneath the surface when using || to provide a fallback value.
In short, || handles values as falsy. ?? handles values as nullish (hence the name).
Which means that with || the second operand is evaluated if the first operand is undefined, null, false, 0, NaN or ''.
?? on the other hand limits this list to only undefined and null.
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