rx-player/src/parsers/texttracks/webvtt/parse_style_block.ts

Canal+ HTML5 Video Player

/**
 * Copyright 2015 CANAL+ Group
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import isNonEmptyString from "../../../utils/is_non_empty_string";
import createDefaultStyleElements from "./create_default_style_elements";

export interface IStyleElements {
  [className: string]: string;
}

/**
 * Parse style element from WebVTT.
 * @param {Array.<Array.<string>>} styleBlocks
 * @return {Object}
 */
export default function parseStyleBlocks(styleBlocks: string[][]): {
  classes: IStyleElements;
  global: string;
} {
  const classes: IStyleElements = createDefaultStyleElements();
  let global = "";

  styleBlocks.forEach((styleBlock) => {
    if (styleBlock.length >= 2) {
      for (let index = 1; index < styleBlock.length; index++) {
        let line = styleBlock[index];
        if (Array.isArray(/::cue {/.exec(line))) {
          line = styleBlock[++index];
          while (
            isNonEmptyString(line) &&
            !(Array.isArray(/}/.exec(line)) || line.length === 0)
          ) {
            global += line;
            line = styleBlock[++index];
          }
        } else {
          const classNames: string[] = [];
          let cueClassLine = /::cue\(\.?(.*?)\)(?:,| {)/.exec(line);
          while (isNonEmptyString(line) && Array.isArray(cueClassLine)) {
            classNames.push(cueClassLine[1]);
            line = styleBlock[++index];
            cueClassLine = /::cue\(\.?(.*?)\)(?:,| {)/.exec(line);
          }

          let styleContent = "";
          while (
            isNonEmptyString(line) &&
            !(Array.isArray(/}/.exec(line)) || line.length === 0)
          ) {
            styleContent += line;
            line = styleBlock[++index];
          }

          classNames.forEach((className) => {
            const styleElement = classes[className];
            if (styleElement === undefined) {
              classes[className] = styleContent;
            } else {
              classes[className] += styleContent;
            }
          });
        }
      }
    }
  });
  return { classes, global };
}