Method _splitOnTopLevelCommas

packages/compiler/src/shadow_css.ts:461–487

* Generator function that splits a string on top-level commas (commas that are not inside parentheses). * Yields each part of the string between top-level commas. Terminates if an extra closing paren is found. * * @param text The string to split * @param returnOnClosingParen Whether to r

(text: string, returnOnClosingParen: boolean)

   * @param returnOnClosingParen Whether to return when exiting the current level of parentheses nesting
   */
  private *_splitOnTopLevelCommas(text: string, returnOnClosingParen: boolean): Generator<string> {
    const length = text.length;
    let parens = 0;
    let prev = 0;

    for (let i = 0; i < length; i++) {
      const charCode = text.charCodeAt(i);

      if (charCode === chars.$LPAREN) {
        parens++;
      } else if (charCode === chars.$RPAREN) {
        parens--;
        if (parens < 0 && returnOnClosingParen) {
          // Found an extra closing paren.
          yield text.slice(prev, i);
          return;
        }
      } else if (charCode === chars.$COMMA && parens === 0) {
        // Found a top-level comma, yield the current chunk
        yield text.slice(prev, i);
        prev = i + 1;
      }
    }

    // Yield the final chunk
    yield text.slice(prev);
  }

  /*
   * convert a rule like :host-context(.foo) > .bar { }