Method has

static/katex/katex.mjs:12962–12964

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

(name)

  has(name) {
    return this.current.hasOwnProperty(name) || this.builtins.hasOwnProperty(name);
  }
  /**
   * Get the current value of a name, or `undefined` if there is no value.
   *