There is an electron framework that gives you a stripped down browser to build your user interface for the desktop application. In my case, I am using jQuery for DOM navigation, Sequelize to talk to my sqlite database and a couple other libraries.
Let's say I have a text field where the user can type a movie name. My database stores a couple hundred movie names. So I would like to offer the user autocomplete suggestions.
Typically, I would use something like this to register a jQuery handler (this will echo field input back to console):
$('#movie-search-field').on('input', (event) => {
console.log(event.target.val())
})
With sequelize, you would typically have a model (say, Movie) and query it like so: Movie.findAll(). Here comes the problem:
If I register my handler like so:
Movie.findAll().then((movies) => {
$('#movie-search-field').on('input', (event) => {
/*Use movies here to build and show a suggestions list*/
})
})
then it never gets triggered. I have verified that the .then clause is entered by printing movies to console from within it.
On the other hand, if I try to query the database from inside the handler:
$('#movie-search-field').on('input', (event) => {
Movies.findAll().then((movies) => {
/*Use movies to build and show a suggestions list*/
})
})
then the handler exits before the promise is resolved and no suggestions are shown.
How could I use the database query results in my event handler?
You could just make a simple callback
$('#movie-search-field').on('input', (event) => {
getResults(function(movies) {
/* Display your movies */
})
})
function getResults(callback) {
Movies.findAll().then((movies) => {
/*Use movies to build and show a suggestions list*/
callback(movies)
})
}
So when a user types in the input box it will request the suggestions and then when it returns them it will call the function (callback) and then you can display them
Turns out I made some unrelated mistakes in my event handler code and so the approach I described above works just fine:
Movie.findAll().then((movies) => {
$('#movie-search-field').on('input', (event) => {
/*Use movies here to build and show a suggestions list*/
})
})
Also, if you are doing several database queries and would like your handler to have access to all of those, you can do:
let movies = Movie.findAll()
let tickets = Ticket.findAll()
Promise.all([movies, tickets]).then(values => {
let [movies, tickets] = values
/* register your handlers here and pass the data to them */
$("#some-selector").on('input', {movies: movies, tickets: tickets}, (event) => {
let movies = event.data.movies
let tickets = event.data.tickets
/* some event handling code that uses both movies and tickets */
})
})
Related
Hopefuly someone can assist/direct me here.
I'm making use of the webshare API on my site. The site contains an array of posts that will have a share link. This is built using a foreach and all have unique urls to use. I want to add a share button to each of those images. I currently have it working on a singular instance but unable to get it to loop through all the share buttons.
Here is the current script:
const shareButton = document.querySelector('.share-button');
const url = document.querySelector('.post-link a').href;
shareButton.addEventListener('click', event => {
if (navigator.share) {
navigator.share({
title: 'Check out this ad I saw on ...',
url
}).then(() => {
console.log('Shared');
})
.catch(console.error);
}
});
I'm really struggling with how to get it to loop through all share buttons and not just be usable on the first instance.
Apologeis if this is simple.
For a start, you need to add a click listener to all buttons, not just the first. You can do this exclusively when the API is supported, else, you may want to hide the buttons. Here's the modified script (note that you need to get the URL of each post individually, see the comment):
const shareButtons = document.querySelectorAll('.share-button');
if ('share' in navigator) {
shareButtons.forEach((shareButton) => {
shareButton.addEventListener('click', () => {
// Get the URL from the dataset or query the DOM.
const url = shareButton.dataset(url);
navigator.share({
title: 'Check out this ad I saw on ...',
url
}).then(() => {
console.log('Shared');
}).catch(console.error);
});
});
} else {
shareButtons.forEach((shareButton) => {
shareButton.style.display = 'none';
});
}
My code works fine when I write in browser localhost:4200/pay;id=1. This show Pay component with credit card fields generated by a external javascript (This javascript script is loaded from this component). But if i come from another component to this, Pay component doesn't show the credit card fields but load external script. How can I fix this?
My code
first.component.ts
let datos = {
id:'6'
}
this.router.navigate(['pay',datos]);
pay.component.ts
ngOnInit(): void {
this.loadScripts();
}
loadScripts() {
this.dynamicScriptLoader.load('2payjs').then(data => {
// Script Loaded Successfully
console.log('All elements loaded successfully')
this.loadElement();
}).catch(error => console.log(error));
}
loadElement(){
let that = this;
let id = this.router.snapshot.paramMap.get('id');
window.addEventListener('load', function() {
// Initialize the JS Payments SDK client.
let jsPaymentClient = new TwoPayClient('AVLRNG');
// Create the component that will hold the card fields.
let component = jsPaymentClient.components.create('card');
component.mount('#card-element');
// Handle form submission.
document.getElementById('payment-form').addEventListener('submit', (event) => {
event.preventDefault();
/// Extract the Name field value
const billingDetails = {
name: document.querySelector('#name').value
};
// Call the generate method using the component as the first parameter
// and the billing details as the second one
jsPaymentClient.tokens.generate(component, billingDetails).then((response) => {
//console.log(response.token);
let data = {
token:response.token
}
}).catch((error) => {
console.error(error);
});
});
});
}
const navigationExtras: NavigationExtras = {
queryParams: {
id: 1,
},
queryParamsHandling: 'merge'
};
this.router.navigate(['pay'], navigationExtras);
you need navigationExtras in order to create params in your router link and able to fetch by another component
Already solved. I just delete window load event listener.
I'm making Todo List project (Pure js) and I'm trying to bind backend (node.js/express.js) with frontend. I'm stuck on the axios.delete(). All i want it to do is:When button "delete" is clicked, delete that item from the page and from the database, but I don't know how to pass the id of that item.
I am new to JavaScript.
const deleteData = () => {
axios.delete('http://localhost:3000/delete/:id', {
})
}
const deleteData = (id) => {
axios.delete('http://localhost:3000/delete/${id}', {
})
}
Did you tried this?
look for Template strings:
https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Template_literals
Suppose I have pageA where I listen for a firebase document changes
export default {
mounted() {
this.$f7ready(() => {
this.userChanges();
})
},
methods: {
userChanges() {
Firebase.database().ref('users/1').on('value', (resp) => {
console.log('use data has changed');
});
}
}
}
Then I go to pageB using this..$f7.views.current.router.navigate('/pageB/')
If on pageB I make changes to the /users/1 firebase route I see this ,message in the console: use data has changed, even though I'm on a different page.
Any way to avoid this behavior, maybe unload the page somehow?
I tried to stop the listener before navigating away from pageA using Firebase.off() but that seems to break a few other things.
Are you properly removing the listener for that specific database reference? You'll have to save the referenced path on a dedicated variable to do so:
let userRef
export default {
mounted() {
this.$f7ready(() => {
this.userChanges();
})
},
methods: {
userChanges() {
userRef = Firebase.database().ref('users/1')
userRef.on('value', (resp) => {
console.log('use data has changed');
});
},
detachListener() {
userRef.off('value')
}
}
}
That way you only detach the listener for that specific reference. Calling it on the parent, would remove all listeners as the documentation specifies:
You can remove a single listener by passing it as a parameter to
off(). Calling off() on the location with no arguments removes all
listeners at that location.
More on that topic here: https://firebase.google.com/docs/database/web/read-and-write#detach_listeners
I just have a question to find out if this is possible:
So what I am doing is when I submit a post I wait for it to complete then update the user object in firebase to insert a time-stamp.
This is fine and works but when the time-stamp is inserted it is causing other subscriptions that are subscribed to changes in the user object to update.
What I want to do it update the user object without causing other subscribers to be updated.
Here is where I am updating the timestamp:
I tried commenting out this line of code which stops the data duplication issue on screen but I need this code to run as I need to update the timestamp when a post is submitted.
this.af.database.object('users/' + x[0].uid + '/lastPostAt').set(timestamp)
.then(x => { this.dialogsService.showSuccessDialog('Post Submitted'); });
Here is where I am subscribing to all the posts:
subscribeAllPosts(): Observable<Post[]> {
return this.af.database.list('/posts')
.map(Post.fromJsonList);
}
Here is where I am creating the array of posts in my constructor to display via a loop in the html:
this.activeItem = this.items[0];
this.postsService.subscribeAllPosts()
.subscribe(posts => {
let container = new Array<PostContainer>();
for (let post of posts) {
this.getEquippedItemsForUsername(post.username).subscribe(
x => {
try {
container.push(new PostContainer(post, x[0].equippedItems));
} catch (ex) { }
}
);
}
this.postContainers = container;
});
In the inner subscription it gets the equippedItems for the user of the post:
getEquippedItemsForUsername(username: string) {
return this.usersService.subscribeUserByUsername(username);
}
Which in turns calls:
subscribeUserByUsername (username: string) {
return this.af.database.list('users' , {
query: {
orderByChild: 'username',
equalTo: username
}
});
}
In the HTML it loops through the postContainer[]:
<li *ngFor="let item of postContainers">
So all that works the issue as stated is that if I do not have the following commented out then the posts will be duplicated more and more as the posts are submitted. If I refresh the app then the posts will show the correct non duplicated posts until another post is submitted.
this.af.database.object('users/' + x[0].uid + '/lastPostAt').set(timestamp)
.then(x => { this.dialogsService.showSuccessDialog('Post Submitted'); });
EDIT: Solved by splitting up logic.