Method has

src/Namespace.ts:72–75

* Detect whether `name` has a definition. Equivalent to * `get(name) != null`.

(name: string)

     * `get(name) != null`.
     */
    has(name: string): boolean {
        return this.current.hasOwnProperty(name) ||
               this.builtins.hasOwnProperty(name);
    }

    /**
     * Get the current value of a name, or `undefined` if there is no value.