vue.js, how to load directive before page is loaded - javascript

I have a directive that controls what buttons someone can see based on their user role:
import { store } from '../store/';
import * as types from '../store/types';
const hide = vnode => {
if (vnode.elm.parentElement) {
vnode.elm.parentElement.removeChild(vnode.elm);
}
};
export const userRole = {
update(el, binding, vnode) {
const userId = store.getters[types.GET_USER_ID];
const { value, modifiers } = binding;
if (value.role) {
if (Reflect.has(modifiers, 'manager')) {
if (value.role[0] !== userId) hide(vnode);
}
};
Then I'll have a button like this:
<vue-button
v-userRole.manager="{role: job.role}"
#click.prevent.stop="e => payoutJob(job.id)"
>
Button Text
</vue-button>
All the buttons will show on the page before the user directive loads. So tons of buttons flash on the page. And then 2 seconds later only two buttons show, as that is what they have permission to see. How do I prevent this?
I would want at the very least, no buttons to appear on the page until the logged in user is matched against the user role directive file.
User information is stored in location storage, in vuex and every page that loads checks for a signed in user.

The way you have created this I think means that this will always happen - your directive is removing the HTML only after it has been created. For the element not to have been created in the first place you need instead to use a v-if or similar. I can see two ways to fix this, one a work-around as a minimal change to what you have, the other I would consider a better solution (but it is of course up to you).
To work around your problem have all of your buttons with a style of display:none and then in your directive either delete the elemet or clear the style (or change the class - however you choose to implement it). That way at least the button won't appear.
However, a better fix, I think, is to create your own component with a userRole property. That component will then do the check you have above (for example through a computed property) and then show or hide the component as required.
EDIT
I ran a quick fiddle to test the principals behind what you were doing - just changing the hook from update to inserted may fix it. Obviously your code will be more complex so your milage may vary ;).

I would focus on Vue instance - https://v2.vuejs.org/v2/guide/instance.html - I think you might use beforeCreate.
Also another idea as Euan Smith wrote, use v-if and put in your data true/false information of loading rights (set it false, and when the role is known set it to true).

Related

Why does v-dialog reset another element's visibility toggle?

Been hacking at this for days, hopefully there are some Vuetify wizards around.
Here's the situation: I have rendered a set of v-expansion-panels and if one of them is expanded, it also shows an arrow button (display: none is toggled by clicking on v-expansion-header). Upon that button click, my aim is to show a dialog.
Problem: Once dialog is prompted with the button click, the button display toggle is reversed. It disappears as soon as you click on the button to prompt a dialog, and appears again once the v-expansion-panel is collapsed.
How it should be: The arrow button should always be visible as long as the v-expansion-panel is expanded, regardless of whether it is clicked to see the dialog or not.
Here's a codepen replicating and illustrating the problem.
Any thoughts would be much appreciated!
It has to do with using style directly on the element.
Use v-show instead of toggling the styles by hand:
<v-btn v-on="on" class="ml-1" width="36px" v-show="expanded[i]">
Update your data to hold an array for the pannels
data () {
return {
dialog: false,
expanded: [false, false, false]
}
}
And update your toggleMoveUp method to update expanded instead of using HTML ids.
toggleMoveup(i) {
this.$set(this.expanded, i, !this.expanded[i])
this.show=true;
}
Notes:
You need to use Vue.set when updating an array
You should not rely on HTML ids, if you use your components in more than one place at a time you'll run into multiple ids.
Why didn't your approach work? I'm guessing that vuetify is updating an element's style property, but doesn't take care of retaining already existing values so your display:none gets erased.
Posting a solution a colleague helped with. This also works with any array size (which is more of a real life scenario in dynamic webapps). It implements a created() lifecycle hook that adds an expanded: false property to each element in the array, which we can use to keep track of the expand state and toggle the button visibility. Here's the codepen.
However, in general, it is recommended in this scenario to actually make an independent component <v-expansion-panels /> and in the parent component actually loop the components. That would solve the state problems on its own already, since each component maintains their own state in their scope.

VueJS Material.io Drawer component variable binding

Currently I'm learning VueJS and I'm working with http://vuematerial.io.
I have build an application with several pages - each of them contains a sidebar (the drawer component https://vuematerial.io/components/drawer).
Since I don't want to copy and paste the same drawer component code over and over again in each page, I just want to create one sidebar component, which I'll then import on each page.
So far, so good.
This is working fine.
But now - I want to be able to open and close the sidebar.
Just before, when the component was directly in the page, it was easy - just a variable assignment with a boolean value to whether show or hide the sidebar.
But now, it seems very hard for me, to synchronize the property over the components.
Let me show you the current new code to clarify what's the problem:
So, this is the page component:
<md-toolbar class="md-primary">
<md-button class="md-icon-button" #click="showSidebar=true">
<md-icon>menu</md-icon>
</md-button><span class="md-title">Dashboard</span>
</md-toolbar>
<Sidebar v-bind:showSidebar="showSidebar"></Sidebar>
So that's the Vue Structure - you can see - I want to bind the showSidebar property.
That's how I'm implementing it within the page
import Sidebar from './sidebar.vue';
export default {
data: function () {
return {
showSidebar: false
}
},
components: {
Sidebar: Sidebar
},
And now the Sidebar component itself:
<md-drawer v-bind:md-active.sync="showSidebar">
The sidebar component then fetches the value over a property like this:
export default {
name: 'sidebar',
props: ['showSidebar'],
And this seems to work!
I can click on the menu button on the page, set the property to true - and the sidebar shows! Great! But.. When I click outside of this sidebar, this warn message appears - and - furthermore - I can't reopen it again on a new click. It closes, but I can't open it again, until I completely reload the page.
How can I be able to solve that?
I have also thinked about using events, since the drawer component seems to listen on events, but I wasn't successful.
That's the current code from the drawer component: https://github.com/vuematerial/vue-material/blob/dev/src/components/MdDrawer/MdDrawer.vue
I hope that it was clear, what my problem is.
I hope, anyone can help me out.
This is my first question here - so please be nice :)
/EDIT:
Opps, here is the warn message:
[Vue warn]: Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders. Instead, use a data or computed property based on the prop's value. Prop being mutated: "showSidebar"
I'm not a Vue pro - still learning it myself - but I think I can see what is going on here.
I think the warning in particular is because you have a prop AND a data property of the same name. Try removing the data setting. You can change the props setting to this:
props: {
showSidebar: {
type: Boolean,
default: false
}
}
See if that fixes it. Also, given how you seem to be using this, I'd suggest looking into using Vuex. The documentation is good and it could really help manage your app. Possibly even fix that issue with reopening the drawer.
Edit:
After reviewing this user's code more closely (connected with them on discord), I've determined the issue is that while the process of opening the sidebar was managed by a property on the parent component, the act of closing it was strictly occurring in the child. When you have data bound like that from parent to child, you need to be sure to update the source (the parent component) of the relevant changes. In Vue, those changes are only pushed one direction. To pass info up to the parent, you have to $.emit events.
My current recommendation is to add a custom event to the sidebar component tag on the parent component:
<Sidebar v-bind:showSidebar="showSidebar" v-on:hide-sidebar="showSidebar=false"></Sidebar>
And then change the close tag in the child component to this:
<span class="md-title" #click="$emit('hide-sidebar')">FleaMaster</span>
Hopefully this information helps someone else as well!

REACT.JS - how to update multiple children on parents state change by one of children

I am struggling for a few days with React, and all the tutorials saying how magnificent it is make me feel that somebody is tricking me :) Learning curve especially while i need to comunicate children-parent-children is so annoying! Anyways...
Consider such a situation:
I have multiple buttons. Each button has its own type. There may be mutiple buttons with one type making a group. Whole idea is to have buttons enabling other buttons, and disabling other ones.
I provide pen to see working example, however imagine i have buttons of types:
settingsOn - it enables all the buttons of type settings
settings - disabled at the begining, enabled after clicking settingsOn button
next - it enables all the buttons of type answer
answers - like settings, enabled after clicking next button.
Normal button looks like this:
<MyButton name='next' type="next" check={() => this.checker("next")} toggle={this.toggler.bind(this)} />
Parent send toggle function and check function with parameters to child.
Only settingOn and next are enabled at beginining. It is made by App.state.next set to true and App.state.answers to false. If App.state.answers is false all the components of type answers are disabled.
Now, everything seems to be working here however one last thing is not:
If i press button "next" it checks what is parent's state.answer and sets it to true (check console log in my pen for confirmation). However changing parent's this.state.answer to true doesnt rerender components of type answer.
To be honest i wanted to make it less messy and learn React, but it seems i could do it via jQuery in one hour a few days ago :/ Is there a good solution for my problem? Should i come back to jQuery and forget React? Or i am one step from solving the problem?
Please help!
Link to codepen
Here's a couple of things I noticed on your codepen that stood out as possible issues.
onClicked(){
this.setState = { answer: this.props.toggle("answer") };
// should be
this.setState({
answer: this.props.toggle("answer)
});
}
Another observation is on componentDidMount you're setting a default state with this.setState({ answer: false, isActive: this.props.check("next") }), I would move these default states to the constructor() as it'd avoid a rerender.
I'm not exactly sure if this is an anti-pattern or not, but I'd avoid setting/getting state like
this.setState({
[type]: !this.state[type]
// instead use
type: !this.state.type
})
Finally I think I was able to get a working component of what you were asking, see this codepen.io. Hopefully this helps, happy coding!

React render, change radio button programmatically

I was creating a Dropdown component for React. Inside the dropdown, I have a form of radio group buttons.
<DropdownButton />
<DropdownForm />
In the DropdownButton, I have an state to know if it is open or not. Depends on that, DropdownForm it's hidden or not (using display: none).
The use case is: User selects a radio button, click apply and something happen. However, if user selects some radio button, and mouse out the dropdown (without clicking the apply button), the one that is selected should be the one that I get from the store.
Something like:
render: function () {
...
if(store.getSomeParam() != this.state.someParam && !this.props.isOpen){
someParam = store.getSomeParam()
}
Then the radio buttons are like:
<input checked={someParam == "something"} ... />
It doesn't really work. It re-renders but it doesn't change the button that is checked. I also tried with refs:
this.refs.myInput.getDOMNode().checked = true
But still nothing. Is this a correct behaviour?
The only solution I found so far is not using a css hiding class (display: none). So what I do is that the DropdownButton renders the DropdownForm depending on if it's open or not (so if you close it, you are forcing DropdownForm to unmount). Then when opening again, it is taking the values from the store (getInitialState) and it shows the correct radio button selected. But, I am not sure if this is the best solution and if there is any drawback in unmounting the component instead of just css hiding it.
This probably has nothing to do with React at all.
Most browsers don't validate the value of the checked attribute, but merely if it is there or not: http://jsfiddle.net/7jzm7gvw/
Just set the checked attribute to either true or null:
<input checked={someParam == "something" ? true: null} ... />
TL;DR: You must use the componentDidMount lifecycle method, not render, to work with the rendered dom nodes directly.
I was struggling with this as well, and after doing some online research I figured I might as well look into it for myself. Here's what I came up with:
Use the componentDidMount lifecycle method and update whatever you need to in there. Here's a Pen I used to prototype this, and I think it looks okay: http://codepen.io/gholts/pen/GpWzdb
You could drop this in pretty easily to what your'e working on by just putting a componentDidMount method on your object and doing it there. I used document.getElementById but you could definitely use jQuery or whatever else you wanted in there, as once the component has mounted it's available to DOM selectors.
I'm using this now to update 20 radio button groups (so it has to check a prop for three different states and update accordingly) and it loads instantly.
Hope it helps! I used the ES6 class syntax in my Pen, you should check it out if you have some time to refactor :) It's fun.
EDIT: So I figured it out, I'm a dummy. You don't need to do the whole document.getElementById business that I was doing. Just use your this.refs.whichever.getDOMNode().checked = true and it'll work, so long as you do it in componentDidMount. It works there because there is an actual DOM element on the page at that point.

A web interface (draggable elements, remembering state) similar to Wufoo

The question I have is very specific. I wanted to have an app where I can create forms, as on Wufoo, with easy to use interface. Which means, draggable elements.
My problem is that I cannot figure out how will the state be saved in the database once the use changes the ordinal position of the form elements. I can do the front-end side, and there are libraries available for that but how do I save a particular instance of the form in the backend so that the next time use logs in, the order is same.
I would love to use Django for this app. So, the basic classes I can think of are:
class Form(models.Model):
"""...objects..."""
class TextField(models.Model):
"""...objects..."""
#FK to Form()
class TitleArea(models.Model):
"""...objects..."""
#FK to Form()
I can also have specific ID's on the elements in the HTML form:
<input id="Field2" name="Field2" type="text"/>
How do they (Wufoo) do this? Is my Model not correct? I know it is naive. Thanks.
You can use ModelForm to create forms using a model instance. Just save the model after a user is done editing, and then when you create the form for them again use the model as an instance to your ModelForm (or formset):
form = YourForm(instance=model_instance)
hidden input fields for the win.
suppose:
$("#submitForm").click(function() {
// Check out the state of the union and change the hidden fields accordingly..
// Something like:
for (var i = 0; i < $(".orderedElements").length; i++) {
$("#ordered-" + ((Number) i + 1)).attr('value', $(".orderedElements").eq(i).attr('id'));
}
});
If you catch my drift.
Well, a good place to start is to think about a use-case. If I'm a user, what am I going to need available to me, to build a form? Textfields, sure -- but what else? Is the form going to have a title? A URL? An expiration date?
When you have this kind of information plotted out, then you can start building out your models in Django.

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