isNull (value) {
    return value === null
  }
Return whether the provided value is `null`.

@example
import { utils } from 'js-data';
const a = null;
const b = { foo: "bar" };
console.log(utils.isNull(a)); // true
console.log(utils.isNull(b)); // false

@method utils.isNull
@param {*} value The value to test.
@returns {boolean} Whether the provided value is `null`.
@since 3.0.0