getType
Returns the native type of a value.
Return 'undefined' or 'null' if the value is undefined or null.
Otherwise, use Object.prototype.constructor.name to get the name of the constructor.
typescript
const getType = (v: any) =>
  v === undefined
    ? "undefined"
    : v === null
    ? "null"
    : v.constructor.name.toLowerCase();
typescript
getType(new Set([1, 2, 3])); // 'set'
getType(null); // 'null'
getType(Deno), "object";