The type of the input value.
The value to be checked.
true if the value is an extensible object, otherwise false.
An extensible object is an object to which new properties can be added.
This function only returns true for actual object values. It avoids the
coercion behavior of Object.isExtensible, which returns false for all
non-object (primitive) values.
| Value | Result | Object.isExtensible |
|---|---|---|
Object.seal( {} ) |
false |
false |
Object.freeze( {} ) |
false |
false |
{} |
true |
true |
[] |
true |
true |
null |
false |
false |
undefined |
false |
false |
123 |
false |
false |
Determines whether the provided value is an extensible object.