![Check if the provided value is of the specified type](https://javascriptsource.com/wp-content/uploads/2021/12/Check-if-the-provided-value-is-of-the-specified-type-702x526.jpg)
Ensure the value is not undefined
or null
using Array.prototype.includes()
. Compare the constructor
property on the value with type
to check if the provided value is of the specified type
.
const is = (type, val) => ![, null].includes(val) && val.constructor === type;
// Examples
is(Array, [1]); // true
is(ArrayBuffer, new ArrayBuffer()); // true
is(Map, new Map()); // true
is(RegExp, /./g); // true
is(Set, new Set()); // true
is(WeakMap, new WeakMap()); // true
is(WeakSet, new WeakSet()); // true
is(String, ''); // true
is(String, new String('')); // true
is(Number, 1); // true
is(Number, new Number(1)); // true
is(Boolean, true); // true
is(Boolean, new Boolean(true)); // true