how to get Previous Route in Angular 4 app - javascript

I have 2 routes defined as homepage and page1. I am going to page1 from homepage by this.router.navigation(with some queryparams).Now once i go to page1, i have some filters,which i can add to get particular data from api.Once i add those filter i change the page1 url by this.router.navigation(with some queryparams).After adding/deleting multiple filter , my url changes many times..Now i have a back button which upon click should navigate me to Homepage.
1.I have tried using history.back/location.back.But i have to click multiple times.(i see that navigationstart gets called multiple times)
2.i have tried a solution using rxjs pairwise
But i am not able to get the previous page(homepage).
3.This is just a situation.Basically i have to get the route of the preious page.I can't hard code the path in backFunc,Because this has to be generic for all of my other similar types of pages.I can come to page1 from any other page, and should be able to go back to the respective page.
Am i missing something very obvious , does Angular 4 provides any way to tackle this?

I'm slightly confused by the question but it should be as simple as just navigating to the homepage by using router.navigate. Failing that, try using https://angular.io/api/common/Location service's back function.

router.navigate has extra parameters like "replaceUrl".
If you set it to true (when you change query params), the browser will consider you don't change page. So an history.back will works.
Have a look at https://angular.io/api/router/NavigationExtras.
this.router.navigate(['/page1'], {replaceUrl: true, queryParams:{...}});

Related

Create multi page design with single URL

My goal is to create multi screens in one single page.Depending upon the action the user will be able to navigate from one screen to another screen.I have shared the images below
When the user clicks on any of the categories ,it will navigate to a second screen.
While clicking back it will again comeback to the first screen without change in URL.I have tried creating a full page modal and could not achieve this kind of functionality.I am not sure whether it should be done as a modal with multiple screens.
Please suggest me any method I can achieve this.
What you are likely referring to is creating an SPA or Single Page Application. This can be done through 'Vanilla' JavaScript at great effort or via one of many JavaScript Libraries or Frameworks.
Reactjs, Angular and Vuejs are probably the most common.
IF you were to use Reactjs then you could use what's called React Router. React Router would do what you want to do very easily. Doing it in Vanilla JavaScript would require a great deal of work or it would be very ugly.
However you did ask, so one way of doing would be to use JavaScript to load an iFrame or to make a top level parent element display: none and another to then display:...
Also if you are thinking of something less hacky, but not something as sophisticated as React or it's peers, then check this link out for a relevant article. Perhaps it's a path forward that you would prefer.
https://dev.to/rishavs/making-a-single-page-app-in-ye-good-olde-js-es6-3eng
To help rookies like me, you can make a single page app or SPA, or a dynamic page that updates based on user actions with a single URL, in vanilla Javascript. You don't have to use a framework.
There are 3 concepts you need to understand:
The server doesn't see past the # in the URL
You need to tell your code what screen you want to display. Normally you would have URL.com/page-you-are-on and click a link to go to URL.com/page-you-want
However, in a single page app, you don't go to different URLs. So how does it work? You use a fragment identifier or a pound symbol. #
The # in the URL doesn't get recognized by the server. So URL.com/page#page1 and URL.com/page#page2 to the server is the exact same URL.com/page.
So you can use the URL to indicate to the server what page you want, in your single page app.
A Router can decide what to show based on the # URL fragment
So your page loads at URL.com/page#page-you-want. You need to inspect the URL and get the piece past the #. You inspect the URL, and split it on the #. That means you get page-you-want. Your code then uses that to decide what content to display. The function or file that does this is commonly called a router because it routes to the file or function you want displayed.
Once you know what to show, dynamically update the DOM
This is where the magic happens. Your website looks at the URL, gets everything past the #, sends it to function that decides what to display. You now need to display it.
The DOM has lots of functions and methods that help it update and create various things. It could be as simple as this:
function displayPageAbout() {
// the router calls this if the URL is URL.com/page#about
let pageSection = document.getElementById('pageSection') //this is where the page will be displayed
//create the div and give it content
let page = document.createElement('div');
page.textContent = 'This is the About Page'
//add the div to the spot on the page where the content should go
pageSection.appendChild(page);
}
That is basically it.
If found these two examples and tutorials useful in understanding what it is, and how it could work.
https://blog.jeremylikness.com/blog/build-a-spa-site-with-vanillajs/
https://dev.to/rishavs/making-a-single-page-app-in-ye-good-olde-js-es6-3eng
Good luck!

Ionic-1 Navigation

I am working on an Ionic-1 App. I am terrible confused in managing the back history of my app. Consider this scenario:
Start from home page then
Does a 3 step user registration process
After the end of user registration redirect to records page
Now clicking back button (hard or soft back) I want to navigate back to home instead of cycling through user registration process. There are other scenarios like this where back behavior needs to be modified. Are there any references around to implement back behavior systematically? Should I manually define view hierarchy tree structure and somehow figure out where in tree current view is and then go to parent?
As per my suggestion you should pass parameter say 'extraparams' in your url and set it value to 'home'.And on record page controller then make a function on back button say 'goBack()' where you can check if value of 'extraparams' is 'home' and then use $state.go() to navigate to home view.
If you can keep and maintain each and every section using state approach then you can redirect to home page or what ever the page you prefer to redirect to.In that way you have to implement back button like this way, $state.go('homeSate');
or if you can keep 3 steps(registration) as sub states and have try by injecting $rootScope to your controller in which allows you to access your parent(home).

JS main app which uses routing to show dialogs and such?

I'm wondering if I can have a JavaScript-based application which has a main "template" as a background/main app of some sorts mixed with some URL routing to show dialogs and such? say, here's a short example:
Main app displays google map and whatnot. URL: /#
User clicks some menu item and it displays an options dialog. URL: /#options
User goes to a sub-options menu. URL: /#options/advanced
User closes the main option dialog, back to main app. URL: /#
User puts some coordinates in URL and the map locates it. URL:/#coords/100/100
The main idea here is to keep the map visible (and other stuff that I want to show in that template, too) in the background while using the URL to either display dialogs, forms or even to control the google map itself - BUT that if the user goes to, for example, /#options on first load, the app should load everything and then show the options dialog, okay?
Basically, I'd like to have a "main state" page which contains the most important part of my app, but I'd like to use url-routing for displaying dialogs and executing actions, that users can bookmark in the future and share and so on. I dunno how is this idea/concept called, so that's why I'm asking.
Also, what can I use to archieve something like this? I know this is kind of an open question, but I'm aiming for a JavaScript-based app/framework (TypeScript works too). I don't know if Angular2 + ui-router can do this, or even how should I google this?...
If Angular2+ui-router can do it, then great! but how?. If there are any other frameworks or combinations please provide an example! I've read about vue.js, react.js and so on, but vue.js seemed too simple and react.js still makes me feel uneasy mixing HTML inside the JS files, it just feels unnatural. Thanks in advance for any pointers you can provide! :)
Angular 2 can accomplish this. One way would be to have just one component. This component shows your map.
Your logic can watch for changes to the URI parameters and show/hide options accordingly. Since these parameters are not always present, you would use optional parameters.
While your app is running, you can add event listeners to buttons and links that should change the view state. When the user clicks a Select City button, the event listener could direct him to a URI with the appropriate parameter: ;view=dialog;target=city (Angular 2 uses matrix uri notation by default)
The component would be listening for changes in the parameters and react accordingly.
ngOnInit() {
this.route.params.forEach((params: Params) => {
// this is executed every time new URI parameters arrive
this.viewType = params['view'];
this.target = params['target'];
//todo: update the model to match new parameters
});
}

How to restore previous state of angular controllers

I need to keep controllers' state in angular ,for improving some user experiences, during user is visiting different pages.
For instance I have a list, which is created via a directive, and it has a pagination section, so imagine when a user go to page 20 and choose an item, they'll be redirected to the detail page, but when they click back button and return to the previous page they see the first page of the list which is not convenient and they expect to be on page 20 again.
I've come up with several options:
Using a dialog to display second page (item detail), so they can close that modal and return to the previous form without any change.
Redirecting users to the second page with a parameter in URL and then return them with that parameter to understand what page number they have been before.
Keeping some crucial variable globally to store controller state and using them when user comes back.
But I think there should be better ideas like keeping controllers' state during redirection.
Any idea would be appreciated.
Redirecting users to the second page with a parameter in URL and then return them with that parameter to understand what page number they have been before.
I prefer this because you get the added benefit of staying on page 20 when you do a page refresh. Options 1 and 3 do not give you this added benefit. Path params are also bookmark friendly.
Another alternative for you to look into that is almost as good is localstorage
or cookies. I dont think these options are better than your 2 though.

How to jump 2 pages before using iron router?

I want to jump to the previous page using iron router. Normally, I would have used the history.back() function but in this case, I use yield templates.
The page I am in is reached using myWebsite.com/page which redirect to myWebsite.com/page/sub-page in order to display the default yield content. Tell me if it is not clear enough, I can edit and provide the code.
To sum it up, my previous page is 2 pages behind. I tried history.back(2) or history.back(-2)but it does not change anything to the normal behavior of the function. How should I do?
I could point directly to the second page but if the user uses the myWebsite.com/page url to access it, my back button would not work.
EDIT: It appears that it was my condition for checking if the history was at least 2 pages which didn't work. Moreover, I should use history.go(-2) instead of history.back()
I will post a proper answer.
Here is the code:
var numberOfEntries = window.history.length;
//check if the history is big enough
if (numberOfEntries>2){
// if it is, jump two pages before
history.go(-2);
}else {
//if it is not, use the default path
Router.go("home");
}

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