Below I have a basic template that has a numerical input form. When you type a number in the form and click Add a list of Divs get created. The Divs are created with a class of "synth" and an id of "synth" + a number. The numbers go in succession based on a counter.
I want to not only store this information in the database but do so in a manner that (eventually) when a user logs in they will have access to their list of Divs as a "saved state" from their previous log in.
I am not even sure if I am going about this in an appropriate manner. I am simply sticking the createSynth() function in the Collection insert for lists. I have a feeling to do this "correctly" I should have two events that work in parallel - one sending to the lists Collection and the other to the dom/Template. These two blocks would then exchange data (some how) which in conjunction create the illusion of a "saved state".
Below is the code I have thus far.
HTML
<head>
<title></title>
</head>
<body>
{{> start}}
</body>
<template name="start">
<input id ="amount" type ="number" />
<input id ="submit" type="button" value="Add" />
<div id="applicationArea"></div>
</template>
Javascript
var lists = new Meteor.Collection("Lists");
var counter = 0;
counterSynth = 0;
if (Meteor.isClient) {
'use strict';
Template.start.events({
'mousedown #submit' : function () {
var amount = document.getElementById("amount").value;
for(i=0;i<amount;i++) {
lists.insert({SoundCircle:createSynth()}); // I am inserting the entire function call, is this the right path?
}
function createSynth() {
var synth = document.createElement("div");
synth.className = "synth";
synth.id = "synth" + (counterSynth++);
applicationArea.appendChild(synth);
};
},
});
}
if (Meteor.isServer) {
Meteor.startup(function () {
// code to run on server at startup
});
}
You have to use a slightly different approach to this, basically just insert your stuff into the collection, and use handlebars to get it out. I'm not entirely sure what you were doing but you should get a good idea with the below
Server js
synths = new Meteor.Collection('synths'); //This will store our synths
Client js:
synths = new Meteor.Collection('synths'); //This will store our synths
Template.start.events({
'mousedown #submit' : function () {
var amount = document.getElementById("amount").value;
for(i=0;i<amount;i++) {
lists.insert({class:"synth", id:counterSynth});
}
},
});
Template.start.synth = function() {
return synths.find(); //This gives data to the html below
}
HTML:
{{#each synth}}
<div class="{{class}}" id="synth{{id}}">
Synth stuff here
</div>
{{/each}
It's probably best to dynamically recreate the DIVs every time you need them on the client, so the DIV is not stored on the server. If you really want to hard code/store the DIV on the server you would need to simply save the HTML as a string, to a Meteor collection.
Related
I have a simple <firebase-query> tag, and I'd like to manipulate some of the data before having it displayed through a <dom-repeat>. For example, I need to turn some fields into links, and also parse some dates.
So, I need to get the data once it's ready, loop through each item, and change some of the values.
To do that, I have an observer on the data to detect when it's ready. However, I can't figure out how to loop through the data from that JavaScript function. For some reason, for(var i in items) doesn't work, although the items do exist.
Here is the component:
<dom-module id="cool-stuff">
<template>
<firebase-query id="query" path="/items" data="{{items}}"></firebase-query>
<template is="dom-repeat" items="{{items}}" as="item">
[[item.name]]<br />
[[item.date]]<br />
</template>
</template>
<script>
Polymer({
is: 'ix-table',
properties: {
items: {type: Object, observer: "_itemsChanged"},
}
itemsChanged: function(data) {
// how do I loop through the data received from firebase-query?
console.log(data);
}
});
</script>
</dom-module>
Ideally, all I'd want to do in the observer function is something like:
for(var i in data) {
obj = data[i];
obj.name = '<a href="/item/"+obj.key>'+ojb.name+'</a>';
}
But I can't seem to be able to loop through the data.
Inside the observer function, console.log(data) returns some weird stuff like this:
Array[o]
0: Object (which contains a proper item)
1: Object (same)
2: Object (same)
Update:
Here is a screenshot of what console.log(data) returns (from inside the observer):
The array seems to be populated with all the objects, but it shows as Array[0]. So it won't let me loop through them.
Update 2:
Thanks to arfost here is the solution:
<script>
Polymer({
is: 'ix-table',
properties: {
items: {type: Object},
}
observers: [
'_itemsChanged(items.splices)'
],
_itemsChanged: function(changeRecord) {
if (changeRecord) {
changeRecord.indexSplices.forEach(function(s) {
for (var i=0; i<s.addedCount; i++) {
var index = s.index + i;
var item = s.object[index];
console.log('Item ' + item.name + ' added at index ' + index);
// do whatever needed with the item here:
this.items[index].name = "New name";
}
}, this);
}
},
});
</script>
<firebase-query> results
Note that <firebase-query> results in an array of objects. Let's say your database contained the following items under /notes/<USER_ID>/:
Your <firebase-query> would look similar to this:
<firebase-query
id="query"
app-name="notes"
path="/notes/[[user.uid]]"
data="{{notes}}">
</firebase-query>
(where user is bound to <firebase-auth>.user).
Assuming the user is logged in, <firebase-query> would then populate its data property (i.e., bound to notes) with the following array:
Note how each object contains a $key property, which corresponds to the item's key seen in the Firebase console's Database view.
You could then iterate notes directly with <dom-repeat>:
<template is="dom-repeat" items="[[notes]]">
<li>
<div>key: [[item.$key]]</div>
<div>body: [[item.body]]</div>
<div>title: [[item.title]]</div>
</li>
</template>
Binding to HTML strings
You should be aware that the string data bindings are rendered literally in this case, so attempting to set name to obj.name = '<a href="...">' would render the literal string instead of an anchor. Instead, you should declare the tags in your template, and bind the key and name properties inside those tags. So, your observer could be replaced with this:
<template is="dom-repeat" items="{{items}}" as="item">
<a href$="/item/[[item.key]]">[[item.name]]</a><br />
[[item.date]]<br />
</template>
Iterating an array
The following note is only relevant if you prefer to mutate the data before displaying it...
When iterating an array, you should avoid for..in because it doesn't guarantee order of iteration, and because it may iterate over enumerable properties you might not necessarily care about. Instead, you could use for..of (assuming ES6 is available to your app):
for (let note of notes) {
note.title += ' ...';
}
or Array.prototype.forEach():
notes.forEach(function(note) {
note.title += ' ...';
});
I thinks I have run into the same issue as you.
It come from the way firebase query is getting the array, the way polymer obersvers works, and is hidden by the fact that the javascript console is reference based when it show the objects.
In fact what really happen here, is that firebase query is creating an empty array, which trigger your polymer observer.
So your function is called as soon as the array is created, but still empty and you can't iterate through, since it's empty. You then log it, where the primitives sub-properties are correctly displayed (array[0])
Then firebase begin to populate the array with the datas. The arrays reference stay the same, so polymer won't fire the observer again, and in the console, when it try to display the array it display the array referenced in the log, which now contains the datas.
I recommend that you use a array mutation observer in place of your simple one as follow
`properties: {
items: {type: Object},
},
,
observers: [
'_itemsChanged(items.splices)'
],`
It will fire every time an object is added to your array, and you would be able to do the work you need :)
I had the link for the documentation on array mutation observer :)
polymer array mutation observer
I hope this will solve your issue,
have a good day.
i don't think i can think of a scenario where you'd need to mutate the data by looping through the array rather than just using computed bindings. like this:
<template is="dom-repeat" items="{{items}}" as="item">
<child-el date="{{_computeDate(item.date)}}"></child-el><br />
<child-el attr1="{{_someOtherConversion(item.prop1)}}"></child-el><br />
<child-el attr2="{{_iPromiseAnyConversionCanBeDoneLikeThis(item.prop2)}}"></child-el><br />
</template>
<script>
_computeDate: function(item) {
//do date converstion
}
Using v-on:click I'd like to set a variable with the id of the div in Vue.JS - how do I reference this?
<div id="foo" v-on:click="select">...</div>
<script>
new Vue({
el: '#app',
data: {
},
methods: {
select: function(){
divID = this.id // ??
alert(divID)
}
}
})
</script>
You can extend your event handler with the event object $event. That should fit your needs:
<div id="foo" v-on:click="select($event)">...</div>
The event is passed on in javascript:
export default {
methods: {
select: function(event) {
targetId = event.currentTarget.id;
console.log(targetId); // returns 'foo'
}
}
}
As mentioned in the comments, `$event` is not strictly necessary, when using it as the only parameter. It's a nice reminder that this property is passed on, when writing it explicitly.
However, nobody will stop you from writing the short notation:
<div id="foo" #click="select">...</div>
Beware that the method will not receive the `$event` object when you add another parameter. You need to explicitly add it at the position you will handle it in the listener. Any parameter order will work:
<div id="foo" #click="select(bar, $event)">...</div>
To find more options of the v-on directive, you can look through the corresponding entry in the vue documentation:
Vue API Documentation - v-on
Inspired by #nirazul's answer, to retrieve data attributes:
HTML:
<ul>
<li
v-for="style in styles"
:key="style.id"
#click="doFilter"
data-filter-section="data_1"
:data-filter-size="style.size"
>
{{style.name}}
</li>
</ul>
JS:
export default {
methods: {
doFilter(e) {
let curTarget = e.currentTarget;
let curTargetData = curTarget.dataset;
if (curTargetData) {
console.log("Section: " + curTargetData.filterSection);
console.log("Size: " + curTargetData.filterSize);
}
}
}
}
Just to highlight another option than the selected answer for the same question, I have a delete button on a record and want to perform an action with the record's unique id (a number). I could do the selected answer as before:
<button :id="record.id" #click="del">×</button>
This leaves the unfortunate reality that my del function needs to pull the id attribute out of the javascript event, which is more about the API (the DOM) than my domain (my app). Also using a number as an element id isn't ideal and could cause a conflict if I do it more than once in a view. So here's something that's just as clear and avoids any future confusion:
<button #click="()=>del(record.id)">×</button>
methods: {
del(id) {
fetch(`/api/item/${id}`, {method:"DELETE"})
}
}
You see, now my del function takes the record id instead of an event, simplifying things.
Note that if you do this wrong, you will invoke your delete function immediately, which is not what you want. Don't do this:~~
<button #click="del(record.id)">×</button>
If you end up doing that, Vue will call the del function every time this html fragment is rendered. Using the anonymous function ()=>del(record.id) will return a function that's ready to be executed when the click event happens.
Actually #nirazul proved this is fine. Not sure what my issue was.
I'm just doing random things on Meteor to get a hang of it before I actually get into more serious things.
Anyway, I'm pretty sure there may be something wrong with the way I associate my helper function with the actual HTML on my project. Basically, I'm trying to make a simple Celsius to Fahrenheit/Fahrenheit to Celsius converter, where the # is converted as soon as a person enters a number. No button clicking involved.
Here's the HTML code:
<head>
<title>My Conversion Script</title>
</head>
<body>
<h1>My Conversion Script</h1>
{{ >converter}}
</body>
<template name="converter">
<b>Enter Celsius:</b>
<input type="text" name="celsius" {{userCalculation}}>
<b>Enter Fahrenheit:</b>
<input type="text" name="fahrenheit" {{userCalculation}}>
</template>
Here's the JS file:
if (Meteor.isClient) {
Template.converter.helpers({
'userCalculation': function() {
Session.get('celsiusCall');
Session.get('fahrenheitCall');
if (!NaN(celsius)) {
return celsius * 9/5 + 32;
} else if (!NaN(fahrenheit)) {
return (fahrenheit - 32) * 5/9;
}
}
});
Template.converter.events({
'keyup .celsius': function(e) {
var celsius = e.target.value;
Session.set('celsiusCall', celsius);
},
'keyup .fahrenheit': function(e) {
var fahrenheit = e.target.value;
Session.set('fahrenheitCall', fahrenheit);
}
});
}
I checked the event handling via console.log and the events work fine. I am making a mistake either the way I'm setting the sessions or the way I'm incorporating the helper function with the HTML itself.
Also, on a side note, am I correct to assume one session can only handle 1 variable?
Edit: The error I get is "Exception in template helper: ReferenceError: celsius is not defined"
It's a variable scoping issue - the variables you define in your template events are not accessible in your template helpers, and vice-versa. So you defined var farenheit = e.target.value in your event handler but farenheit in your helper returns undefined. You'll want to define the variable in both.
Session works as a dictionary of key-value pairs so you can define multiple variables in it, if I understand your question correctly.
Session.set('first', 'a');
Session.set('second', 'b);
Session.keys // {first: 'a', second: 'b'}
You are correctly creating and receiving the session keys but you never assign them to the names of variables you are using. You would need to create variables for the Session.get calls like so:
var celsiusCall = Session.get('celsiusCall');
var fahrenheitCall = Session.get('fahrenheitCall');
Then you could use those vars like you currently are doing so now.
I am struggling to figure out the basic pattern for populating a template with data from a call to an external API in Meteor.
These are the elements in play
A fresh Meteor project, created by running meteor create monkeyproject
The URL of an external API that returns a JSON array. Let's say it's example.com/api/getmonkeys. It returns an array of monkeys, each with a different name.
A Handlebar template called monkeyTemplate with an {{#each}} loop. Let's say it's this:
<template name="monkeyTemplate">
{{# each monkeys}}
One of our monkeys is named {{name}}. <br>
{{/each}}
<input type="button" id="reload" value="Reload monkeys" />
</template>
What I want to happen
When the page loads fill monkeyTemplate with monkeys from our external URL.
When the user clicks the button, call the external URL again to reload the monkeys.
The question
What is a standard pattern for doing the above in Meteor? At the risk of cluttering up the question, I'll include some starting points, as I understand them.
We can populate the template with whatever we return from our Template.monkeyTemplate.monkeys function. How do we fill it with content from an external URL, given that the page will load before the external request is finished?
We can get our JSON by using Meteor.HTTP.call("GET", "http://example.com/api/getmonkeys", callback ). Where do we put this request, and what do we put into our callback function in this situation?
We can control what happens on the server side and what happens on the client side by using the Meteor.isServer/Meteor.isClient conditions, or by putting our code into files called client and server folders. What code needs to be on the server side vs. the client side?
We determine what happens when the button is clicked by attaching a function to Template.monkeyTemplate.events['click #reload']. What goes into our callback function in this situation?
I will refrain from cluttering up the question with my crappy code. I am not looking for anyone to write or rewrite an application for me—I am just looking for the guidelines, standard patterns, best practices, and gotchas. Hopefully this will be instructive to other beginners as well.
I'm not sure if this is the "standard" template, but it serves the purpose pretty well.
Set up two data helpers for the template, monkeys and loading. First one will display the actual data once it's fetched, the latter will be responsible for notifying user that the data is not yet fetched.
Set up a dependency for these helpers.
In created function of the template, set loading helper to true and fetch the data with HTTP call.
In the callback, set the template data and fire the dependency.
html
<template name="monkeys">
{{#if loading}}
<div>Loading...</div>
{{/if}}
{{#if error}}
<div>Error!</div>
{{/if}}
{{#each monkeys}}
<div>{{name}}</div>
{{/each}}
<div><button class="monkeys-reloadMonkeys">Reload</button></div>
</template>
js
var array = null;
var dep = new Deps.Dependency();
Template.monkeys.created = function() {
reloadMonkeys();
};
Template.monkeys.events({
'click .monkeys-reloadButton': function(e,t) {
reloadMonkeys();
};
});
var reloadMonkeys = function() {
array = null;
dep.changed();
HTTP.get('http://example.com/api/getmonkeys', function(error, result) {
if(!error && result) {
array = result;
} else {
array = 0;
}
dep.changed();
});
};
Template.monkeys.monkeys = function() {
dep.depend();
return array ? array : [];
};
Template.monkeys.loading = function() {
dep.depend();
return array === null;
};
Template.monkeys.error = function() {
dep.depend();
return array === 0;
};
How do I access one 'sibling' variable in a meteor template helper, when I am in the context of another? I want to determine whether the user that is logged in and viewing the page is the same user that posted the ride offering, so that I can hide or show the "bid" button accordingly.
For example, here is my template (html) file:
<!-- client/views/ride_offers.html -->
<template name="RideOfferPage">
<p>UserIsOwner:{{UserIsOwner}}</p>
{{#with CurrentRideOffer}}
{{> RideOffer}}
{{/with}}
</template>
<template name="RideOffer">
<div class="post">
<div class="post-content">
<p>Details, Author: {{author}}, From: {{origin}}, To: {{destination}}, between {{earliest}} and {{latest}} for {{nseats}} person(s). Asking ${{price}}.
<button type="button" class="btn btn-primary" >Bid</button><p>
<p>UserIsOwner:{{UserIsOwner}}</p>
</div>
</div>
</template>
And here is my JavaScript file:
Template.RideOfferPage.helpers({
CurrentRideOffer: function() {
return RideOffers.findOne(Session.get('CurrentOfferId'));
},
UserIsOwner: function() {
return RideOffers.find({_id: Session.get('CurrentOfferId'), userId: Meteor.userId()}).count() > 0;
}
});
In the "RideOffer" template, I am able access the variables author, origin, ..., price. But I am unable to access the boolean UserIsOwner. I am, however, able to access the boolean UserIsOwner in the "RideOfferPage" template.
Does anyone know how I can access the boolean UserIsOwner in the "RideOffer" template?
Cheers,
Put the userIsOwner function outside the helper as an anonymous function and then call it from both templates.
Template.RideOfferPage.helpers({
CurrentRideOffer: function() {
return RideOffers.findOne(Session.get('CurrentOfferId'));
},
UserIsOwner: checkUserIsOwner()
});
Template.RideOffer.helpers({
UserIsOwner: checkUserIsOwner()
});
checkUserIsOwner= function() {
return RideOffers.find({_id: Session.get('CurrentOfferId'), userId: Meteor.userId()}).count() > 0;
}
There are several ways to do what you're asking.
In your particular example you are not asking about siblings, but about parents, since the RideOfferPage template renders the RideOffer template. You can access variables in the parent data context (but not helpers) like so:
<template name="RideOffer">
<div class="post">
<div class="post-content">
<!--
other stuff
-->
<p>UserIsOwner:{{../UserIsOwner}}</p>
</div>
</div>
</template>
In other cases, you may have a template being rendered as a sibling of this one. In that case, you can't actually know what the sibling is until the template is actually on the page; however, you can find it in the rendered callback:
Template.foo.rendered = function() {
var current = this.firstNode;
var next = $(currentItem).next(); // or .prev()
if (next.length) {
nextData = Spark.getDataContext(next[0]);
}
// Do something with nextData
};
Finally, you can get the parent context of any rendered DOM element by repeatedly iterating through its parents. This isn't super efficient but I've used it in places where there is extensive drag and drop with DOMFragments moving around on the page:
Template.bar.events = {
"click .something": function(e) {
var target = e.target;
var context = Spark.getDataContext(target);
var parentContext = context;
while (parentContext === context) {
parentContext = Spark.getDataContext(target = target.parentNode);
}
// Do something with parentContext
}
};
I'm curious to know if there is a better way to do the last thing, which may potentially have to iterate through many DOM elements. In any case, you may want to check out my meteor-autocomplete package for this and other cool tricks.