deftjs looks really promising as it adds exactly the necessary things I missed in the MVC implementation of ExtJs.
What I actually miss is a functionality that makes routing possible/ easy. Extjs has a Ext.ux.Router functionality but I formerly used code like this with help of this lib:
initRoutes: function () {
var me = this;
Log.debug('Books.controller.App: initRoutes');
//use PATH.JS library until ExtJs supports routing as Sencha Touch 2.0 does. (see utils\Path)
Path.map("#/home").to(function () {
me.getController('Home').index();
});
Path.map("#/trackingsheet").to(function () {
me.getController('TrackingSheet').index();
});
Path.root('#/home');
Path.listen();
}
As the procedure of creating the crucial parts in deftjs is now exactly the other way around (view creates the controller) I certainly cannot refer to a controller's method and instantiate the view and make it the visible one. I have a pretty simple card layout here - what means only one view can be visible at a time, it is not necessary to go any deeper like this (e.g. make a task pane visible or the like).
What is the preferred way to do it?
I can think of making the Viewport a view factory having some methods like the controller before.
Thanks,
da5id
I solved this problem by using Ext.util.History class in a history context class that can raise an event when the hash changes:
Ext.define('myApp.context.HistoryContext', {
mixins: {
observable: 'Ext.util.Observable'
},
constructor: function(config) {
var me = this;
if (config == null) {
config = {};
}
this.initConfig(config);
Ext.util.History.add('home');
//init Ext.util.History; if there is a hash in the url,
//controller will fire the event
Ext.util.History.init(function(){
var hash = document.location.hash;
me.fireEvent('tokenChange', hash.replace('#', ''));
});
//add change handler for Ext.util.History; when a change in the token occurs,
//this will fire controller's event to load the appropriate content
Ext.util.History.on('change', function(token){
me.fireEvent('tokenChange', token);
});
this.mixins.observable.constructor.call(this);
this.addEvents('tokenChange');
return this.callParent(arguments);
}
});
Then you can inject this context in to your controller, and observe the token change, and implement the action in dispatch method:
Ext.define('myApp.controller.HomeController', {
extend: 'Deft.mvc.ViewController',
inject: [
'historyContext'
],
control: {
appContainer: {},
home: {
click: 'addHistory'
},
about: {
click: 'addHistory'
}
},
observe: {
historyContext: {
tokenChange: "dispatch"
}
},
init: function() {
return this.callParent(arguments);
},
switchView: function(view) {
//change this to get the cards for your card layout
this.getAppContainer().add(Ext.ComponentMgr.create({
xtype : view,
flex : 1
}));
},
addHistory: function(btn) {
var token = btn.itemId;
Ext.util.History.add(token);
},
dispatch: function(token) {
// switch on token to determine which content to load
switch(token) {
case 'home':
this.switchView('view-home-Index');
break;
case 'about':
this.switchView('view-about-Index');
break;
default:
break;
}
}
});
This should be ok for the first level routing (#home, #about), but you need to implement your own mechanism to fetch the token for the second and third level routes. (#home:tab1:subtab1) You can possibly create a service class that can handle fetching the hash and inject the service to each controllers to dispatch.
For further discussion in this topic, go to https://github.com/deftjs/DeftJS/issues/44
Related
I'm using react to retrieve data from parse, manipulate it in my own function, and then update a component in the render.
The problem is that I can't update the state within my own, convoluted function unless I attach a string of bind(this). The entire component looks like this:
React.Component({
getInitialState: function () {
return{
isloading:true
}
},
componentDidMount: function(){
this.myStupidFunction()
},
myStupidFunction : function(){
(
(
(nested parse queries that eventually ...
return an object and set isloading:false).bind(this))
.bind(this))
.bind(this)
},
render: function (){
if (this.state.isloading) {
return(
<Text "...isloading"/>
)
} else {
return(
...actually return important stuff...
)
}
}
})
What is the smarter way to do this? Do I need to really .bind(this) for every nested function?
There are a few ways to maintain the context of your component.
Use ES6 Arrows
If you use ES6 arrows to define your functions. Arrow functions force the inner context of this to be the same as the outer context, regardless of how the function is called.
parse.find({
success: results => {
// this is correct
console.log(this);
}
});
I think this is the most elegant solution, but not all browsers support arrow functions yet.
Use Component Methods
React automatically binds this into each of the top level methods on your component. They are always guaranteed to have the correct context.
onSuccess: function() {
// this is correct
console.log(this);
},
componentWillMount: function() {
parse.find({
success: this.onSuccess
});
}
This is also fairly elegant, in my opinion. It lets React deal with the messiness of context whilst you just write code. However, it can mean that you end up with far too many methods at the top level of your component, so use it sparingly.
As an Argument
Some functions, such as map allow you to optionally pass a context to use as this as a final argument. This allows you to maintain the correct context without .bind(this).
data.map(function() {
console.log(this);
// this is correct
}, this);
This only works for some methods, so it's not really a universal solution.
Alias this
Create a reference to this and use that instead.
var __this__ = this;
parse.find({
success: results => {
// __this__ is correct
console.log(__this__);
}
});
This hack has been around forever in Javascript, but I don't think it's a great way to solve the problem.
Use ES7 Function Bind
For those who like to Javascript on the edge, you could also achieve this using the ES7 function bind syntax proposal — currently implemented in Babel.
parse.find({
success: this::function(results) {
// this is correct
console.log(this);
}
});
This requires using experimental proposal stage features of ES7. You may not want to start using it yet, but it's definitely interesting to be aware of. The value on the left hand side will be bound into the function on the right, as this.
Use a closure at the beginning of the function to capture this. It will be usable in any nested structure. The conventional names for such a closure are self _this and that. I prefer self.
myStupidFunction : function(){
var self = this;
someAsyncCall(1,2, function(result) {
//some nested stuff
anotherAsyncCall(1,2 function(innerResult) {
self.setState(innerResult);
});
});
}
one solution could be using local variable
myStupidFunction:function(){
var that=this
ParseReact.Mutation.Create('Place', {
name: 'New Place',
user: Parse.User.current()
})
.dispatch()
.then(function() {
that.refreshQueries();
});
}
Using ES7 Property Initalizer Syntax, currently implemented in Babel.
The key is the methodName = () => { //method return }
You can read more here.
import React from 'react';
export default class Note extends React.Component {
constructor(props) {
super(props);
this.state = {
editing : false
}
}
render() {
const editing = this.state.editing;
return (
<div>{ editing ? this.renderEdit() : this.renderTask() }</div>
)
}
renderEdit = () => {
return (
<input type="text"
className="edit-input"
autoFocus={true}
defaultValue={this.props.task}
onBlur={this.finishEdit}
onKeyPress={this.checkEnter} />
)
}
renderTask = () => {
const onDelete = this.props.onDelete;
return (
<div onClick={this.edit}>
<span className="task-body">{this.props.task}</span>
{ onDelete ? this.renderDelete() : null }
</div>
)
}
renderDelete = () => {
return (
<button className="delete-btn" onClick={this.props.onDelete}>x</button>
)
}
edit = () => {
this.setState({
editing : true
})
}
checkEnter = (e) => {
if(e.key === "Enter") {
this.finishEdit(e);
}
}
finishEdit = (e) => {
this.props.onEdit(e.target.value);
this.setState({
editing : false
})
}
}
// Note: Sample class from project above.
I want to make a route with has a mandatory parameter. If not, it should fall into
$urlRouterProvider.otherwise("/home");
Current route:
function router($stateProvider) {
$stateProvider.state("settings", {
url: "^/settings/{id:int}",
views: {
main: {
controller: "SettingsController",
templateUrl: "settings.html"
}
}
});
}
Currently both the routes below are valid:
http://myapp/settings //Should be invalid route
http://myapp/settings/123
Any ideas?
Use a state change start listener to check if params were passed:
$rootScope.$on('$stateChangeStart',
function (event, toState, toParams, fromState, fromParams) {
if(toState.name==="settings")
{
event.preventDefault(); //stop state change
if (toParams.id===undefined)
$state.go("home");
else
$state.go(toState, toParams);
}
});
The following solution is valid for ui-router 1.0.0:
.config(($stateProvider, $transitionsProvider) => {
//Define state
$stateProvider.state('verifyEmail', {
parent: 'portal',
url: '/email/verify/:token/:optional',
component: 'verifyEmail',
params: {
token: {
type: 'string',
},
optional: {
value: null,
squash: true,
},
},
});
//Transition hooks
$transitionsProvider.onBefore({
to: 'verifyEmail',
}, transition => {
//Get params
const params = transition.params();
//Must have token param
if (!params.token) {
return transition.router.stateService.target('error', {
type: 'page-not-found',
});
}
});
})
The above will make the :token parameter mandatory and the :optional parameter optional. If you try to browse to the page without the token parameter it will fail the transition and redirect to your error page. If you omit the :optional parameter however, it will use the default value (null).
Remember to use squash: true on the trailing optional parameters, because otherwise you'll also get a 404 if you omit the trailing / in the URL.
Note: the hook is required, because if you browse to email/verify/ with a trailing slash, ui-router will think the token parameter is an empty string. So you need the additional handling in the transition hook to capture those cases.
In my app I had to make required parameters for a lot of routes. So I needed a reusable and DRY way to do it.
I define a constants area in my app to access global code. I use for other things as well.
I run this notFoundHandler at app config time. This is setting up a router state for handling errors. It is setting the otherwise route to this error route. You could define a different route for when a required parameter is missing, but for us this was defined as being the same as a 404 experience.
Now at app run time I also define a stateChangeErrorHandler which will look for a rejected route resolve with the 'required-param' string.
angular.module('app')
.constant('constants', constants)
.config(notFoundHandler)
.run(stateChangeErrorHandler);
// use for a route resolve when a param is required
function requiredParam(paramName) {
return ['$stateParams', '$q', function($stateParams, $q) {
// note this is just a truthy check. if you have a required param that could be 0 or false then additional logic would be necessary here
if (!$stateParams[paramName]) {
// $q.reject will trigger the $stateChangeError
return $q.reject('required-param');
}
}];
}
var constants = {
requiredParam: requiredParam,
// define other constants or globals here that are used by your app
};
// define an error state, and redirect to it if no other route matches
notFoundHandler.$inject = ['$stateProvider', '$urlRouterProvider'];
function notFoundHandler($stateProvider, $urlRouterProvider) {
$stateProvider
//abstract state so that we can hold all our ingredient stuff here
.state('404', {
url: '/page-not-found',
views: {
'': {
templateUrl: "/app/error/error.tpl.html",
}
},
resolve: {
$title: function () { return 'Page Not Found'; }
}
});
// redirect to 404 if no route found
$urlRouterProvider.otherwise('/page-not-found');
}
// if an error happens in changing state go to the 404 page
stateChangeErrorHandler.$inject = ['$rootScope', '$state'];
function stateChangeErrorHandler($rootScope, $state) {
$rootScope.$on('$stateChangeError', function(evt, toState, toParams, fromState, fromParams, error) {
if (error && error === 'required-param') {
// need location: 'replace' here or back button won't work on error page
$state.go('404', null, {
location: 'replace'
});
}
});
}
Now, elsewhere in the app, when I have a route defined, I can make it have a required parameter with this route resolve:
angular.module('app')
.config(routeConfig);
routeConfig.$inject = ['$stateProvider', 'constants'];
function routeConfig($stateProvider, constants) {
$stateProvider.state('app.myobject.edit', {
url: "/:id/edit",
views: {
'': {
template: 'sometemplate.html',
controller: 'SomeController',
controllerAs: 'vm',
}
},
resolve: {
$title: function() { return 'Edit MyObject'; },
// this makes the id param required
requiredParam: constants.requiredParam('id')
}
});
}
I'd like to point out that there shouldn't be any problem with accessing the /settings path, since it doesn't correspond to any state, unless you've used inherited states (see below).
The actual issue should happen when accessing the /settings/ path, because it will assign the empty string ("") to the id parameter.
If you didn't use inherited states
Here's a solution in plunker for the following problem:
accessing the /state_name/ path, when there's a state with url /state_name/:id
Solution explanation
It works through the onBefore hook (UI router 1.x or above) of the Transition service, which prevents transitioning to states with missing required parameters.
In order to declare which parameters are required for a state, I use the data hash like this:
.state('settings', {
url: '/settings/:id',
data: {
requiredParams: ['id']
}
});
Then in app.run I add the onBefore hook:
transitionService.onBefore({}, function(transition) {
var toState = transition.to();
var params = transition.params();
var requiredParams = (toState.data||{}).requiredParams || [];
var $state = transition.router.stateService;
var missingParams = requiredParams.filter(function(paramName) {
return !params[paramName];
});
if (missingParams.length) {
/* returning a target state from a hook
issues a transition redirect to that state */
return $state.target("home", {alert: "Missing params: " + missingParams});
}
});
If you used inherited states
You could implement the same logic via inherited states:
function router($stateProvider) {
$stateProvider
.state('settings', {
url: '/settings'
})
.state('settings.show", {
url: '/:id'
});
}
then you'd need to add the abstract property to the parent declaration, in order to make /settings path inaccessible.
Solution explanation
Here's what the documentation says about the abstract states:
An abstract state can never be directly activated. Use an abstract state to provide inherited properties (url, resolve, data, etc) to children states.
The solution:
function router($stateProvider) {
$stateProvider
.state('settings', {
url: '/settings',
abstract: true
})
.state('settings.show", {
url: '/:id'
});
}
Note: that this only solves the issue with /settings path and you still need to use the onBefore hook solution in order to also limit the access to /settings/.
it is not very well documented, but you can have required and optional parameters, and also parameters with default values.
Here is how you can set required params:
function router($stateProvider) {
$stateProvider.state("settings", {
url: "^/settings/{id:int}",
params: {
id: {}
},
views: {
main: {
controller: "SettingsController",
templateUrl: "settings.html"
}
}
});
}
I never used params with curly brackets, just with the semicolon, like this url: "^/settings/:id", but from what I read, those are equivalent.
For other types of parameters, please see the other half of my answer here: AngularJS UI Router - change url without reloading state
Please note that when I added that answer, I had to build ui-router from source, but I read that functionality has been added to the official release by now.
I often use ajax request for that kind:
$.ajax({
done : function() {
alert( "success" );
},
fail : fonction() {
alert( "error" );
}
})
For one of my project I want to create some default action for each ajax request, and I wonder how can I implement it with JavaScript inheritance.
How I would like it looks like:
// Definition of the custom and global object in order to override some basic ajax options.
MyCustomAjaxObject = new $.ajax();
MyCustomAjaxObject.error( function () { /* some code for a default */});
// Further in the code, at the moment to trigger one of the ajax request
foo = new MyCustomAjaxObject({
url : myDestination,
data : someData
});
Do you know if it's possible to use inheritance of that kind with JavaScript?
$.ajax() as it isn't really designed to be used as a constructor, so inheritance probably won't accomplish what you want easily.
You can create a wrapper for it to modify the options or resulting $.Deferred as desired:
// A) default handler
function customAjax(options) {
if (!options.error) options.error = function () {
// ...
};
return $.ajax(options);
}
// B) always-in-queue handler
function customAjax(options) {
return $.ajax(options).error(function () {
// ...
});
}
And, if you just need to capture ajax events in general, jQuery does include global event bindings:
$(document).ajaxError(function () {
// ...
});
I have a layout view, with an itemView inside it. I have an event in my item view that triggers a save function. Inside that save function I would like to trigger another event that the layout captures.
So in the code below, in the onClickSave modelSaveSuccess I'd like to trigger a function in the parent layout, I have tried this.methodInParent() but it doesnt work
childView
define(["marionette", "underscore", "text!app/templates/client/form.html", "app/models/client"], function(Marionette, _, Template, Model) {
"use strict"
return Backbone.Marionette.ItemView.extend({
events: {
"submit #saveClient": "onClickSave"
},
onClickSave: function(ev) {
ev.preventDefault()
return this.model.save({}, {
success: function() {
console.log('success - trigger ')
},
error: function(request, error) {
console.log(error.responseText)
}
})
}
})
})
A good way to do it without introducing heavy coupling is to use Marionette's event aggregator as in the linked exemple if you use Backbone.Marionette.application.
// in your view
...
success: function() {
app.vent.trigger('myview:modelsaved');
}
...
// in your layout initialize()
...
app.vent.on('myview:modelsaved', function(){
console.log('model saved in itemView');
});
...
If you don't use Backbone.Marionette.Application you can always create your own Backbone.Wreqr.EventAggregator.
I'm using backbone for an app that I'm building. In this app, I have a master view which render a template with 2 other views inside. One header view and another one with some content. The header view is just used to interact with the content view and has specific functions too.
In the header template and content template I have the same piece of code, an hidden DIV with a loader image that is displayed when an ajax call is made. The problem I have is that when I load the app for the first time (or when I refresh the content view), the content view is loading some data from an ajax request, but the loader is showing up in both the header and the content template (like if the ajaxStart() was a global event not attached to the view.
Here is the content view setup:
App.View.Content = Backbone.View.extend({
type:'test',
template: twig({
href: '/js/app/Template/Content.html.twig',
async: false
}),
block:{
test:twig({
href: '/js/app/Template/block/test.html.twig',
async: false
})
},
list:[],
showLoader: function(el){
console.log('loader: ', $('#ajax_loader', el));
$('#ajax_loader', el).show();
console.log('Ajax request started...');
},
hideLoader: function(el){
$('#ajax_loader', el).hide();
console.log('Ajax request ended...');
},
initialize: function(params)
{
this.el = params.el;
this.type = params.type || this.type;
var self = this;
this.el
.ajaxStart(function(){self.showLoader(self.el);})
.ajaxStop(function(){self.hideLoader(self.el);});
this.render(function(){
self.list = new App.Collection.ListCollection();
self.refresh(1, 10);
});
},
refresh:function(page, limit)
{
var self = this;
console.log('Refreshing...');
$('#id-list-content').fadeOut('fast', function(){
$(this).html('');
});
this.list.type = this.type;
this.list.page = page || 1;
this.list.limit = limit || 10;
this.list.fetch({
success: function(data){
//console.log(data.toJSON());
$.each(data.toJSON(), function(){
//console.log(this.type);
var tpl_block = self.block[this.type];
if (tpl_block != undefined) {
var block = tpl_block.render({
test: this
});
$(block).appendTo('#id-list-content');
}
});
$('#id-list-content').fadeIn('fast');
}
});
},
render: function(callback)
{
console.log('Rendering list...');
this.el.html(this.template.render({
}));
if (undefined != callback) {
callback();
}
}
});
As you can see I'm using an ugly piece of code to attach the ajaxStart / ajaxStop event:
this.el
.ajaxStart(function(){self.showLoader(self.el);})
.ajaxStop(function(){self.hideLoader(self.el);});
I use to have it like this:
this.el
.ajaxStart(self.showLoader())
.ajaxStop(self.hideLoader());
But for whatever reason that still undefined on my end, this.el was not defined in the showLoader() and hideLoader().
I was thinking that ajaxStart() and ajaxStop() was attached to the this.el DOM, and that only this view would be able to listen to it. But my headerView which has exactly the same setup (except for the twig template loaded) apparently receive the event and show the loader.
To be sure of this behavior, I've commented out the showLoader() in the content view, and the loader still show up in the header view.
I don't know what I'm doing wrong :(
EDIT (after answer from "mu is too short"):
my content view does now looks like this:
showLoader: function(){
//this.$('#ajax_loader').show();
console.log('Ajax request started...');
},
hideLoader: function(){
this.$('#ajax_loader').hide();
console.log('Ajax request ended...');
},
initialize: function(params)
{
var self = this;
console.log(this.el);
_.bindAll(this, 'showLoader', 'hideLoader');
this.$el
.ajaxStart(this.showLoader)
.ajaxStop(this.hideLoader);
this.render(function(){
self.list = new App.Collection.List();
self.refresh(1, 10);
});
},
...
render: function(callback)
{
console.log('Rendering post by page...');
this.$el.html(this.template.render({
}));
if (undefined != callback) {
callback();
}
}
and my header view:
...
showLoader: function(){
this.$('#ajax_loader').show();
//console.log('Ajax request started...');
},
hideLoader: function(el){
this.$('#ajax_loader').hide();
console.log('Ajax request ended...');
},
initialize: function(params)
{
var self = this;
_.bindAll(this, 'showLoader', 'hideLoader');
this.$el
.ajaxStart(this.showLoader)
.ajaxStop(this.hideLoader);
this.models.Link = new App.Model.Link();
this.render();
},
render: function(callback)
{
this.$el.html(this.template.render({
data: []
}));
if (undefined != callback) {
callback();
}
}
...
But the loader still showing up in the header view template
PS: this.showLoader() was not a typo as I wanted to call the function within the current backbone view.
The context (AKA this) for a JavaScript function depends on how the function is called, not on the context in which the function is defined. Given something like this:
var f = o.m;
f();
When you call o.m through the plain function f, this inside o.m will usually be the global context (window in a browser). You can also use apply and call to choose a different this so this:
f.call(o);
would make this the o that you'd expect it to be. I should mention that you can force your choice of this using bind in most JavaScript environments but I don't want to get too sidetracked.
The point is that this:
this.el
.ajaxStart(this.showLoader)
.ajaxStop(this.hideLoader);
isn't enough to ensure that showLoader and hideLoader will run in the right context; I'm also assuming that the parentheses you had at the end of showLoader and hideLoader were just typos.
The most common way to force a context in a Backbone application is to use _.bindAll in your initialize:
initialize: function(params) {
_.bindAll(this, 'showLoader', 'hideLoader');
//...
That essentially replaces this.showLoader and this.hideLoader with something that's, more or less, equivalent to your wrappers:
function() { self.showLoader(self.el) }
Once you have that _.bindAll in place, this:
this.el
.ajaxStart(this.showLoader)
.ajaxStop(this.hideLoader);
will work fine.
BTW, you don't need to do this:
this.el = params.el;
in your initialize, Backbone does that for you:
constructor / initialize new View([options])
[...] There are several special options that, if passed, will be attached directly to the view: model, collection, el, id, className, tagName and attributes.
And you don't need to do things like this:
$('#ajax_loader', el).show();
either, Backbone gives you a $ method in your view that does the same thing without hiding the el at the end of the argument list; doing it like this:
this.$('#ajax_loader').show();
is more idiomatic in Backbone.
Furthermore, this.el won't necessarily be a jQuery object so don't do this:
this.el.html(this.template.render({ ... }));
in your render, use the cached this.$el instead:
this.$el.html(this.template.render({ ... }));