Function evaluate

resources/vega.min.js:3541–3549

(t)

      ((this.pulse = null), (this.source = null));
    },
    evaluate(t) {
      const e = this._update;
      if (e) {
        const n = this.marshall(t.stamp),
          r = e.call(this, n, t);
        if ((n.clear(), r !== this.value)) this.value = r;
        else if (!this.modified()) return t.StopPropagation;
      }
    },
    run(t) {
      if (t.stamp < this.stamp) return t.StopPropagation;
      let e;