Returns true
if the specified value is undefined
, false
otherwise.
Use the strict equality operator to check if val
is equal to undefined
.
代码片段
const isUndefined = val => val === undefined;
使用样例
isUndefined(undefined); // true
Returns true
if the specified value is undefined
, false
otherwise.
Use the strict equality operator to check if val
is equal to undefined
.
const isUndefined = val => val === undefined;
isUndefined(undefined); // true