Javascript null ¶
Definition ¶
The value null represents the intentional absence of any object value.
It is one of JavaScript’s primitive values and is treated as falsy for boolean operations.
What is the difference between null and undefined in JavaScript ? ¶
null and undefined are JavaScript primitive types.
The meaning of undefined is to say that a variable has declared, but it has no value assigned.
let age //age is undefined
let age = null // age === null
Example ¶
function getVowels(str) {
const m = str.match(/[aeiou]/gi);
if (m === null) {
return 0;
}
return m.length;
}
console.log(getVowels('sky'));