unmapper.js

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

// @flow
import StackFrame from './stack-frame';
import { getSourceMap } from './getSourceMap';
import { getLinesAround } from './getLinesAround';
import path from 'path';

function count(search: string, string: string): number {
  // Count starts at -1 becuse a do-while loop always runs at least once
  let count = -1,
    index = -1;
  do {
    // First call or the while case evaluated true, meaning we have to make
    // count 0 or we found a character
    ++count;
    // Find the index of our search string, starting after the previous index
    index = string.indexOf(search, index + 1);
  } while (index !== -1);
  return count;
}

/**
 * Turns a set of mapped <code>StackFrame</code>s back into their generated code position and enhances them with code.
 * @param {string} fileUri The URI of the <code>bundle.js</code> file.
 * @param {StackFrame[]} frames A set of <code>StackFrame</code>s which are already mapped and missing their generated positions.
 * @param {number} [fileContents=3] The number of lines to provide before and after the line specified in the <code>StackFrame</code>.
 */
async function unmap(
  _fileUri: string | { uri: string, contents: string },
  frames: StackFrame[],
  contextLines: number = 3
): Promise<StackFrame[]> {
  let fileContents = typeof _fileUri === 'object' ? _fileUri.contents : null;
  let fileUri = typeof _fileUri === 'object' ? _fileUri.uri : _fileUri;
  if (fileContents == null) {
    fileContents = await fetch(fileUri).then(res => res.text());
  }
  const map = await getSourceMap(fileUri, fileContents);
  return frames.map(frame => {
    const {
      functionName,
      lineNumber,
      columnNumber,
      _originalLineNumber,
    } = frame;
    if (_originalLineNumber != null) {
      return frame;
    }
    let { fileName } = frame;
    if (fileName) {
      fileName = path.normalize(fileName);
    }
    if (fileName == null) {
      return frame;
    }
    const fN: string = fileName;
    const source = map
      .getSources()
      .map(s => s.replace(/[\\]+/g, '/'))
      .filter(p => {
        p = path.normalize(p);
        const i = p.lastIndexOf(fN);