Checks if value is specifically undefined.
Strict equality check for undefined values. More explicit than checking truthiness.
value to check
true if value is exactly undefined
isUndefined(undefined) // trueisUndefined(null) // falseisUndefined('') // falseisUndefined(0) // falselet x;isUndefined(x) // true Copy
isUndefined(undefined) // trueisUndefined(null) // falseisUndefined('') // falseisUndefined(0) // falselet x;isUndefined(x) // true
Checks if value is specifically undefined.
Strict equality check for undefined values. More explicit than checking truthiness.