Why does typeof(null) return "object"?
According to the document, the `typeof` operator consistently returns “object” when applied to `null`, despite `null` being a primitive data type. This behavior is due to a specification within the JavaScript standard, and cannot be changed without causing issues across many existing scripts.
generated by
gemma3:4b
Table of Contents
1st Explanation
Why does typeof(null) return “object”?
Even though null is a primitive, typeof(null) still returns “object”. One of the most reasonable explanation:
Because the spec says so.
11.4.3 The typeof Operator
The production UnaryExpression : typeof UnaryExpression is evaluated as follows:
- Let val be the result of evaluating UnaryExpression.
- If Type(val) is Reference, then a. If IsUnresolvableReference(val) is true, return “undefined”. b. Let val be GetValue(val).
- Return a String determined by Type(val) according to Table 20.
2nd Explanation
Here is the relevant portion: This is considered a bug, but one which cannot be fixed because it will break too many scripts.