Method stringify

src/core/dom/srcset.js:231–248

* Reconstructs the string expression for this srcset. * @param {function(string):string=} opt_mapper * @return {string}

(opt_mapper)

   * @return {string}
   */
  stringify(opt_mapper) {
    const res = [];
    const sources = this.sources_;
    for (let i = 0; i < sources.length; i++) {
      const source = sources[i];
      let src = source.url;
      if (opt_mapper) {
        src = opt_mapper(src);
      }
      if (this.widthBased_) {
        src += ` ${/** @type {WidthSourceDef} */ (source).width}w`;
      } else {
        src += ` ${/** @type {DprSourceDef} */ (source).dpr}x`;
      }
      res.push(src);
    }
    return res.join(', ');
  }
}

/**