30-seconds-of-code/snippets/isPrimitive.md

isPrimitive

Returns a boolean determining if the passed value is primitive or not.

Use Array.includes() on an array of type strings which are not primitive, supplying the type using typeof. Since typeof null evaluates to 'object', it needs to be directly compared.

const isPrimitive = val => !['object', 'function'].includes(typeof val) || val === null;

isPrimitive(null); // true
isPrimitive(50); // true
isPrimitive('Hello!'); // true
isPrimitive(false); // true
isPrimitive(Symbol()); // true
isPrimitive([]); // false