Right now I have 'user' object with nested object named 'author' with id field in it. How can I define rules for that object?
This code doesn't work:
can('manage', 'Post', { author: { id: id } });
Neither this one (well, it works, but I save rules in localStorage, and saving functions inside of it is not a good idea)
can('manage', 'Post', { 'author': function(author) { ... } });
You can use dot notation:
can('manage', 'Post', { 'author.id': id });
You can find more information about query language and common cases to define rules in CASL docs
Related
I'm trying to use a helper that should return a Collection specifying a subset of the whole Collection with $in using a reactive array from templates:array.
I have
var tags = new ReactiveArray();
and on some event I change the contents of the array, something along the lines of
tags.pushArray(note.tags);
(or maybe I should use .set()?)
My helper is
Template.editor.helpers({
tagslist() {
return Tags.find({ _id: { $in : tags }});
},
});
But then I get an exception in meteor.js:1010 which looks like this
if (allArgumentsOfTypeString)
console.log.apply(console, [Array.prototype.join.call(arguments, " ")]);
In the stack there is compileValueSelector. This seems to indicate that the compilation of the helper is not content with what it finds.
I've also tried to make tags a template local instance, and adding .get() to the tags in the helper query. But with the same result.
Where should I start looking? Am I using ReactiveArray correctly? Is it possible to do what I want, namely have a reactive query based on an ReactiveArray?
I personally have not used ReactiveArray but I assume this same pattern would work. I stick to using ReactiveVar so here is an example that should get you going in the right direction.
Template.editor.onCreated(function () {
const instance = this;
instance.tags = new ReactiveVar([]);
});
Template.editor.helpers({
tagslist() {
const tags = Template.instance().tags.get();
return Tags.find({ _id: { $in : tags }});
}
});
Template.editor.events({
'click .tag'(event, instance){
const tag = this;
const tags = instance.tags.get();
tags.push(tag);
instance.tags.set(tags);
}
});
I've been tasked with implementing selectors in our redux application. Everything I'm reading online about redux selectors talks about React and how you can replace what is in mapStateToProps with a selector. What is the equivalent/where would i do this in a mithril app?
What is the equivalent/where would i do this in a mithril app?
Firstly, you don't need an equivalent, you can just use the exact same selectors that you would in a React application.
Where to call selectors?
You can call the selectors wherever you want, but I recommend calling them as close to where the data is used as possible. Don't call selectors in a component high up in the component hierarchy only to pass the data down via several components before they end up in a component that actually uses the data – unless you have a good reason to do so.
For most cases you can call the selectors inside a view-function, although you might come across cases where you need to call selectors in other lifecycle methods as well. In some applications you might also want to use selectors in m.render as well.
A couple of examples off the top of my head:
Inside the view function when creating DOM-elements
var LoggedinUserDetails = {
view: function () {
return m('', [
m('', getLoggedinUserName(store.getState())), // getLoggedinUserName is a selector
m('img', { src: getLoggedinUserImageUrl(store.getState()) }) // getLoggedinUserImageUrl is a selector
])
}
}
Inside the view function when creating Mithril components
var UserDetails = {
view: function (attrs) {
return m('', [
m('', attrs.user.name),
m('img', { src: attrs.user.imageUrl })
])
}
}
...
m(UserDetails, { user: getLoggedInUserDetails(store.getState()) }) // getLoggedInUserDetails is a selector
Inside m.render
In this example, we have a game that requires us to re-render the whole page after any change.
function onStateChange() {
var state = store.getState();
m.render(document.body, m(Game, {
map: getMap(state),
players: getPlayers(state),
visibleArea: getVisibleArea(state)
}));
}
// Receiving partial state updates from server via websockets
websocket.on('update-map', function (map) {
store.dispatch({ type: 'update-map', payload: map });
});
websocket.on('update-players', function (players) {
store.dispatch({ type: 'update-players', payload: players });
});
// Changing state based on user input
window.addEventListener('keydown', function (event) {
switch (event.key) {
case 'Enter':
store.dispatch({ type: 'move-visible-area-to-next-player' });
break;
}
});
I'm not familiar with Mithril, but Redux state selectors are independent from React. They are just functions that expect state and return a:
a slice of state
or data derived from state
For example, if I my Redux state has an entry named records containg a list of models:
{
records: [ ... ],
}
I could create a selector returning the length:
const numOfRecords = state => state.records.length
Or if my state also keeps track of a sortBy value:
const sortedRecords = state => state.records.sort(sortByFn(state.sortBy))
Selectors can be helpful to increase performance and reduce the need for updates. (reselect is a great module for this).
They are also great for developing modular pieces of code that depend on data stored in application state but don't really want to know where that data comes from.
Is it possible to alter (add more fields for each record) a returned collection in onBeforeAction or similar hook?
I have InvoiceHistory collection which I am paginating through. I also want to display as part of each invoice the company name, business address, email address and VAT registration number - and these four fields are stored in another collection. So I would like to add these four fields to each record returned from InvoiceHistory. If there is another way to do it I am open to suggestions. I am using Alethes meteor pagination which loses the helper fields returned in its itemTemplate when you navigate/browse/page to the second page. Alethes pagination also relies on iron-router, is it maybe possible to achieve what I want with the help of iron-router
========================================================================
#Sean. Thanks. Below is the code that uses meteor publish composite:
if (Meteor.isServer) {
import { publishComposite } from 'meteor/reywood:publish-composite';
publishComposite('invoicesWithCompanyDetails', function(userId, startingDate,endingDate) {
return {
find() {
// Find purchase history for userId and the two dates that were entered. Note arguments for callback function
// being used in query.
return PurchaseHistory.find({Id:userId,transactionDate:{$gte:new Date(decodeURIComponent(startingDate)),
$lt:new Date(decodeURIComponent(endingDate))}});
},
children: [
{
find() {
return CompanySharedNumbers.find(
{ _id:"firstOccurrence" },
{ fields: { companyName: 1, companyAddress: 1 } }
);
}
}
]
}
});
}
Router.route('/store/invoices/:_username/:startingDate/:endingDate', { //:_startingDate/:_endingDate
name: 'invoices',
template: 'invoices',
onBeforeAction: function()
{
...
},
waitOn: function() {
var startingDate = this.params.startingDate;
var endingDate = this.params.endingDate;
return [Meteor.subscribe('systemInfo'),Meteor.subscribe('testingOn'),Meteor.subscribe('invoicesWithCompanyDetails',startingDate,endingDate)];
}
});
Pages = new Meteor.Pagination(PurchaseHistory, {
itemTemplate: "invoice",
availableSettings: {filters: true},
filters: {},
route: "/store/invoices/:_username/:startingDate/:endingDate/",
router: "iron-router",
routerTemplate: "invoices",
routerLayout: "main",
sort: {
transactionDate: 1
},
perPage: 1,
templateName: "invoices",
homeRoute:"home"
});
Instead of adding new fields to all your document. What you could do is to add a helper to load a company document :
Template.OneInvoice.helpers({
loadCompany(companyId){
return Company.findOne({_id: companyId});
}
});
And use it in your template code:
<template name="OneInvoice">
<p>Invoice id: {{invoice._id}}</p>
<p>Invoice total: {{invoice.total}}</p>
{{#let company=(loadCompany invoice.companyId)}}
<p>Company name: {{company.name}}</p>
<p>Company business address: {{company.businessAddress}}</p>
{{/let}}
</template>
This way, the code is very simple and easily maintainable.
If I'm understanding you correctly, this sounds like a job for a composite publication.
Using a composite publication you can return related data from multiple collections at the same time.
So, you can find all your invoices, then using the company ID stored in the invoice objects you can return the company name and other info from the Companies collection at the same time.
I've used composite publications before for complex data structures and they worked perfectly.
Hope that helps
Refer to the code below please:
Router.route('/posts/:_id', function () {
this.render('Post', {
to: 'content',
data: function () {
return Posts.findOne({id: this.params._id});
}
});
});
If a Post object has title and body fileds in MongoDB, I can access them from Post.html template like
<h4>Post title: {{title}}</h4>
<h3>Post body: {{body}}</h4>
I would like to access Post object from Post.js in a template helper function. Is it possible?
Update:
According to this question: Meteor data-context with iron-router, I can access the data variable like this:
Template.Post.rendered = function() {
console.log(this.data)
}
Is there a way to do this inside Template.Post.events ?
Seems like you are looking for the Template.currentData() method.
Template.example.events({
'click #test':function(e,t){
console.log(Template.currentData())
}
})
update Seems like using currentData have differents behaviors depending the case check this
So it seems like if you want to use it, you it should be inside a DOM element.
Template.post.events({
'click h4':function(){
console.log(Template.currentData()) // and should return the title.
}
})
based on the stubalio says.
Inside an event handler, returns the data context of the element that
fired the event.
In my meteor app I have the following handler, returning a "contributor" record:
Template["IntroductionWizard_Step_1"].helpers({
contributor: function(n) {
return ContributorCollection.findOne({contributorName: ""});
}
});
This record is being used in a reactive template:
<input type="text" id="name" name="name" class="form-control-element" value="{{contributor.contributorName}}"
As I understand, the reason for this template to track changes to this record is because it came from a reactive source.
What I was wondering is whether it would make sense to create an actual Contributor object, and return that instead of just a record. But, if I was to do that, this object would not be observed for changes, or would it?
Another words, can a more traditional object-oriented approach be used with meteor, having such Model objects as observable and reactive (two-way bindings) as those Collection records?
You can do whatever you want – Javascript is a prototype based, so it's enough to get the right prototype and modify it.
To enhance behavior of collection element, you need to use transform method:
Contributor = function(doc) {
_.extend(this, doc); // initialize object with contents of doc
...
};
Contributors = new Meteor.Collection('contributors', {
transform: function(doc) {
return new Contributor(doc);
},
});
Now you can add methods to contributor's prototype:
_.extend(Contributor.prototype, {
someFunction: function() {...},
otherFunction: function() {...},
...
});
If you want to adjust collection methods, it's even simpler:
Contributors._findOne = Contributors.findOne;
Contributors.findOne = function() {
var contributor = Contributors._findOne.apply(this, arguments);
if(!contributor) {
// initialize and save new contributor
...
}
return contributor;
};
With these techniques you can inject the desired behavior to collection and its elements.