enhance: wait for element

.travis.yml

@@ -1,7 +1,7 @@
 language: node_js
 sudo: false
 node_js:
-  - 8
+  - 12
 script:
   - npm i
   - npm run build:doc

package.json

@@ -1,12 +1,16 @@
 {
   "name": "macaca-wd",
-  "version": "3.3.2",
+  "version": "3.3.3",
   "description": "Macaca wd client",
   "keywords": [
     "macaca",
     "webdriver",
     "wd"
   ],
+  "files": [
+    "lib/**/*.js",
+    "wd/lib/**/*.js"
+  ],
   "main": "./lib/macaca-wd.js",
   "repository": {
     "type": "git",

wd/lib/commands.js

@@ -844,15 +844,14 @@ commands.hasElement = function(using, value){
  * opts with the following fields: timeout, pollFreq, asserter.
  * asserter like: function(browser , cb) -> cb(err, satisfied, return_value)
  */
-commands.waitFor = function(){
+commands.waitFor = function() {
   var cb = findCallback(arguments);
   var fargs = utils.varargs(arguments);
   var opts;
   // retrieving options
-  if(typeof fargs.all[0] === 'object' && !(fargs.all[0] instanceof Asserter)){
+  if (typeof fargs.all[0] === 'object' && !(fargs.all[0] instanceof Asserter)) {
     opts = fargs.all[0];
-  } else
-  {
+  } else {
     opts = {
       asserter: fargs.all[0],
       timeout: fargs.all[1],
@@ -864,15 +863,17 @@ commands.waitFor = function(){
   opts.timeout = opts.timeout || 1000;
   opts.pollFreq = opts.pollFreq || 200;
 
-  if(!opts.asserter) { throw new Error('Missing asserter!'); }
+  if(!opts.asserter) {
+    throw new Error('Missing asserter!');
+  }
 
   var _this = this;
   var endTime = Date.now() + opts.timeout;
 
   var unpromisedAsserter = new Asserter(
     function(browser, cb) {
       var promise = opts.asserter.assert(browser, cb);
-      if(promise && promise.then && typeof promise.then === 'function'){
+      if (promise && promise.then && typeof promise.then === 'function') {
         promise.then(
           function(res) { cb(null, true, res); },
           function(err) {
@@ -913,7 +914,7 @@ commands.waitFor = function(){
  * opts with the following fields: timeout, pollFreq, asserter.
  * asserter like: function(element , cb) -> cb(err, satisfied, el)
  */
-commands.waitForElement = function(){
+commands.waitForElement = function() {
 
   var cb = findCallback(arguments);
   var fargs = utils.varargs(arguments);
@@ -922,7 +923,7 @@ commands.waitForElement = function(){
   var opts;
 
   // retrieving options
-  if(typeof fargs.all[2] === 'object' && !(fargs.all[2] instanceof Asserter)){
+  if (typeof fargs.all[2] === 'object' && !(fargs.all[2] instanceof Asserter)) {
     opts = fargs.all[2];
   } else if(fargs.all[2] instanceof Asserter) {
     opts = {