Method whenSignal

src/core/data-structures/signals.js:52–74

* Returns the promise that's resolved when the signal is triggered. The * resolved value is the time of the signal. * @param {string} name * @return {Promise }

(name)

   * @return {Promise<TimestampDef>}
   */
  whenSignal(name) {
    let promiseStruct = this.promiseMap_?.[name];
    if (!promiseStruct) {
      const result = this.map_[name];
      if (result != null) {
        // Immediately resolve signal.
        const promise =
          typeof result == 'number'
            ? Promise.resolve(result)
            : Promise.reject(result);
        promiseStruct = {promise};
      } else {
        // Allocate the promise/resolver for when the signal arrives in the
        // future.
        promiseStruct = new Deferred();
      }
      if (!this.promiseMap_) {
        this.promiseMap_ = map();
      }
      this.promiseMap_[name] = promiseStruct;
    }
    return promiseStruct.promise;
  }

  /**
   * Triggers the signal with the specified name on the element. The time is