Function escapeBlocks

packages/compiler/src/shadow_css.ts:1103–1148

(
  input: string,
  charPairs: Map<string, string>,
  placeholder: string,
)

}

function escapeBlocks(
  input: string,
  charPairs: Map<string, string>,
  placeholder: string,
): StringWithEscapedBlocks {
  const resultParts: string[] = [];
  const escapedBlocks: string[] = [];
  let openCharCount = 0;
  let nonBlockStartIndex = 0;
  let blockStartIndex = -1;
  let openChar: string | undefined;
  let closeChar: string | undefined;

  for (let i = 0; i < input.length; i++) {
    const char = input[i];
    if (char === '\\') {
      i++;
    } else if (char === closeChar) {
      openCharCount--;
      if (openCharCount === 0) {
        escapedBlocks.push(input.substring(blockStartIndex, i));
        resultParts.push(placeholder);
        nonBlockStartIndex = i;
        blockStartIndex = -1;
        openChar = closeChar = undefined;
      }
    } else if (char === openChar) {
      openCharCount++;
    } else if (openCharCount === 0 && charPairs.has(char)) {
      openChar = char;
      closeChar = charPairs.get(char);
      openCharCount = 1;
      blockStartIndex = i + 1;
      resultParts.push(input.substring(nonBlockStartIndex, blockStartIndex));
    }
  }

  if (blockStartIndex !== -1) {
    escapedBlocks.push(input.substring(blockStartIndex));
    resultParts.push(placeholder);
  } else {
    resultParts.push(input.substring(nonBlockStartIndex));
  }

  return new StringWithEscapedBlocks(resultParts.join(''), escapedBlocks);
}

/**
 * Object containing as keys characters that should be substituted by placeholders