js console autosuggest

console_suggest.js

function getSuggestions(input) {
  var result = {};
  var target = getTarget(input);
  if (!target) {
    return [];
  }
  var keys = getAllKeys(target);
  var part = getLastPart(input);
  for (var i = 0; i < keys.length; i++) {
    if (keys[i].toLowerCase().startsWith(part.toLowerCase())) {
      result[keys[i]] = true;
    }
  }
  return Object.keys(result).sort();
}

function getTarget(input) {
  var target = window;
  var parts = [];
  var rest = input;
  while (rest) {
    // TODO: support array[number], object[string] and object(expression)
    var part = (/\.\w+$/).exec(rest);
	if (part && part.length && part[0].length) {
	  parts.unshift(part[0].slice(1))
	  rest = rest.slice(0, part[0].length * -1);
	} else {
	  var lastPart = (/\w+$/).exec(rest);
	  if (lastPart && lastPart.length && lastPart[0].length) {
	    parts.unshift(lastPart[0])
	  }
	  break;
	}
  }
  while (target instanceof Object && parts.length > 1) {
    target = target[parts.shift()]
  }
  return target;
}

function getAllKeys(obj) {
  var result = [];
  var target = obj;
  while (target instanceof Object) {
    result = result.concat(Object.getOwnPropertyNames(target));
    target = Object.getPrototypeOf(target);
  }
  return result;
}

function getLastPart(input) {
  return input.split(".").pop();
}

getSuggestions('console.log(document.b')