rollbar/src/utility/traverse.js

Effortlessly track and debug errors in your JavaScript applications with Rollbar. This package includes advanced error tracking features and an intuitive interface to help you identify and fix issues more quickly.

import * as _ from '../utility.js';

function traverse(obj, func, seen) {
  var k, v, i;
  var isObj = _.isType(obj, 'object');
  var isArray = _.isType(obj, 'array');
  var keys = [];
  var seenIndex;

  // Best might be to use Map here with `obj` as the keys, but we want to support IE < 11.
  seen = seen || { obj: [], mapped: [] };

  if (isObj) {
    seenIndex = seen.obj.indexOf(obj);

    if (isObj && seenIndex !== -1) {
      // Prefer the mapped object if there is one.
      return seen.mapped[seenIndex] || seen.obj[seenIndex];
    }

    seen.obj.push(obj);
    seenIndex = seen.obj.length - 1;
  }

  if (isObj) {
    for (k in obj) {
      if (_.hasOwn(obj, k)) {
        keys.push(k);
      }
    }
  } else if (isArray) {
    for (i = 0; i < obj.length; ++i) {
      keys.push(i);
    }
  }

  var result = isObj ? {} : [];
  var same = true;
  for (i = 0; i < keys.length; ++i) {
    k = keys[i];
    v = obj[k];
    result[k] = func(k, v, seen);
    same = same && result[k] === obj[k];
  }

  if (isObj && !same) {
    seen.mapped[seenIndex] = result;
  }

  return !same ? result : obj;
}

export default traverse;