code: function encodeStylePolygon_(fillStyle, strokeStyle, encodedStyles) {
    encodeStyleFill_(fillStyle, encodedStyles);
    if (strokeStyle !== null) {
      encodeStyleStroke_(strokeStyle, encodedStyles);
    }
  }
docs: Transform an {@link import("ol/style/Fill.js").default} and an
  {@link import("ol/style/Stroke.js").default} into a logical sequence of characters and put the result into
  the given encoded styles's array.
  @param {import("ol/style/Fill.js").default} fillStyle Fill style.
  @param {import("ol/style/Stroke.js").default} strokeStyle Stroke style.
  @param {Array<string>} encodedStyles Encoded styles array.
  @private
  @hidden