Checks if the provided value is of the specified type.
undefined
or null
using Array.prototype.includes()
.Object.prototype.constructor
to 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;
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
JavaScript, Type
Checks if the provided argument is array-like (i.e. is iterable).
JavaScript, Type
Checks if the a value is an empty object/collection, has no enumerable properties or is any type that is not considered a collection.
JavaScript, Type
Checks if the provided value is an object created by the Object constructor.