I have a web page that displays a Vuetify date-picker component.
When the page is loaded or when the month is changed, I make an AJAX call that runs an SQL query to return the dates in that specific month when a particular event occurred.
Then, I only want to make these specific dates clickable.
As per the Vuetify documentation, the allowed-dates attribute allows you to do this.
After some experimentation, I have come across some unexpected difficulty:
The allowed-dates attribute takes in a function instead of, for example, an array. So, I had to create a function that will consult an "allowed dates" array that is returned by my AJAX call
Furthermore, the function is called when the date-picker is rendered and NOT when the AJAX call returns, so I end up with no dates being activated or only one date being activated on only the last date of the month being activated.
Am I missing something? is the allowed-dates attribute not responsive? I would prefer to stick with Vuetify since I am using it for the rest of the UI, but I am willing to switch to something else if a solution cannot be found.
There's some confution when an example in docs says:
You can specify allowed dates using arrays, objects, and functions.
But in API allowed-dates consumes only functions.
I guess the answer is to correctly define allowedDates function.
You first need to create an empty reactive array, then assign data into it via AJAX call, and in allowedDates function you just be able to compare the displayed page of dates with the dates in the array.
So the code is...
<v-date-picker
v-model="date"
:allowed-dates="allowedDates"
/>
...
data: () => ({
date: '2022-01-11',
allowedDatesArray: [],
}),
mounted() {
this.getAllowedDates();
},
methods: {
allowedDates(val) {
return this.allowedDatesArray.includes(val);
},
async getAllowedDates() {
this.allowedDatesArray = [];
await //...your AJAX call that must assign allowedDatesArray
}
}
I created a sandbox at CodePen where you may test this solution with some static dates that loading asynchronously using Promise.
In your solution you need to replace Promise with your AJAX call.
Related
I have a single page dashboard application. I've been playing around with setInterval which works quite well for just updating the data without reloading the page. I put the setInterval function within mounted(), not sure if it best belongs there but works okay.
However! This SPA has a ton of filters. You can search, you can select dropdowns, you can sort, on and on. Say the initial page load has 1000 rows and you use the search bar to narrow it down to one row/one result. Now setInterval runs and it will re render all 1000 rows. This is the method (defined in methods: {} section that initially loads the data and the method used in mounted() with setInterval):
getData: function (arg1, arg2) {
API.getSomeData(arg1, arg2).then(resp => {
getTicketData(resp.data);
this.$data.loading = false;
});
}
Is there a way to account for the filters when it comes to the setInterval piece?
Any and all insight is appreciated.
It sounds like you might be overwriting the same data property when you fetch data from the API and when you filter on it. If that's the case, you should use a computed property to display the filtered records to the user instead.
computed: {
tableRows() {
if (this.filters)
return this.filter()
return this.apiData
}
Where this.filter() will filter down this.apiData without overwriting its contents. Then you can iterate over tableRows in your template (e.g. v-for="row in tableRows") to display those to the user.
If you want to remove some of this logic from your Vue component, you might consider using a Vuex store to both fetch/update from your API and also to calculate the filters.
this.$store.dispatch('fetch_on_interval', { interval: 1000 })
this.$store.dispatch('set_filters', { ...filters })
this.$store.getters('table_data')
Your getter would check the filters and return whatever is relevant. Vuex getters can be used in computed properties too.
Per the docs you can add the attribute use-input to a QSelect component to introduce filtering and things of that nature: https://quasar.dev/vue-components/select#Native-attributes-with-use-input.
However, if you type something into one of these fields and click outside of it, the text gets removed.
Is there any way to grab that text in Vue before it gets removed and do something with it?
Since v1.9.9 there is also a #input-value event described in the q-select api.
As the api says it's emitted when the value in the text input changes. The new value is passed as parameter.
In the examples there's a filter function, so there you can save it in a data variable:
methods: {
filterFn (val, update, abort) {
update(() => {
this.myDataVariable = val;
})
}
}
I have problem understanding why THE SAME mutation fails to refresh data displayed in components (although it does change underlying vuex store data!) if it is called from one of the components, but it does refresh the data if called from another component?
I am updating Filter objects stored in store this way: state.report.filters[], where filters is array of Filter objects.
const state = {
report: {
filters: [], // array of Filter objects
...
}
}
My mutation looks for a filter in the array and substitutes the whole Filter object.
const mutations = {
setFilter: (state, newFilterValue) => {
let changedFilter = state.report.filters.find(filter => {
return filter.fieldName === newFilterValue.fieldName;
});
changedFilter = newFilterValue;
}
}
The mutation is called from a method of Filter class defined like this (separate module):
import { store } from './store';
export class Filter {
constructor ({
...
} = {}) {
this.operators = []; // Array of Operator objects
this.value = []; // Array of values - in this case Dates
};
updateOperator (operatorName) { // this mutation refreshes components when executed
this.operator[0] = new Operator(operatorName);
store.commit('setFilter', this); // whole object passed to the mutation
};
updateValue (newValue) { // this mutation changes store value, but fails to refresh components
this.value[0] = newValue; // newValue is a Date
store.commit('setFilter', this);
};
};
The app displays data in rows (each Filter has a separate row), each row contains cells, of which one contains components dedicated to Filter's value and Operator. These dedicated components receive as props callback functions which are methods of the Filter object. They execute the callback functions when a new value is entered passing the value to the Filter which then updates a relevant property and calls the mutation passing in both cases the whole Filter object as payload.
// TABLE CELL COMPONENT displaying filter value and operator
<template>
<td>
<operator-component
:iconName="proppedFilterObject.operator.iconName"
:callback="proppedFilterObject.updateOperator.bind(proppedFilterObject)"
></operator-component>
<value-component
:date="proppedFilterObject.value[0]"
:callback="proppedFilterObject.updateValue.bind(proppedFilterObject)"
></value-component>
</td>
</template>
<script>
export default {
props: ['proppedFilterObject'] // whole filter object
};
</script>
// OPERATOR COMPONENT
<template>
<div #click.stop="chooseOperator">
{{ iconName }} // some operator value display
</div>
</template>
<script>
export default {
methods: {
chooseOperator () {
const modal = new ChooseOperatorModal({
callback: this.callback // this displays another modal for receiving data. The modal calls the callback.
});
},
},
props: ['callback', 'iconName']
};
</script>
// VALUE COMPONENT
<template>
<date-picker v-model="computedDate"> // THIRD PARTY COMPONENT
</date-picker>
{{ date }} // additional display to verify if there's a problem within 'date-picker'
</template>
<script>
import DatePicker from 'vue2-datepicker'; // THIRD PARTY COMPONENT
export default {
components: { DatePicker },
computed: {
computedDate: {
get: function () {
return this.date;
},
set: function (newValue) {
this.callback(newValue);
}
}
},
props: ['callback', 'date']
};
</script>
So, if eg. I enter new operator value from Operator component, everything refreshes. When I enter a new value in the value component, the mutation is executed and store value changed, but displayed data are not refreshed. However, if afterwards I change an operator all the components will refresh and value will get displayed. Even if I change operator in a different Filter object(!). Ie:
a) Change in report.filters[0].value - display not refreshed, but...
b) then change report.filters[1].operator - both report.filters[1].operator AND PREVIOUSLY CHANGED report.filters[0].value get refreshed(?!).
What can be a reason of such behaviour? Where to look for the problem?
Some additional remarks:
1) I am using a third party component "vue2-date-picker" for date choice and display. However it does not seem to be responsible for the problem, as if I try to display the new value just in {{ }} notation it behaves the same way. I have used the date picker in other components and there it functions correctly as well.
2) In the code samples I left out most imports/exports and other seemingly irrelevant elements to keep the question reasonably short.
There are a lot of problems with the code and several of them are contributing to the problems you're seeing. A full, thorough answer that addresses all of these problems would be ridiculously long so instead I will skim through them without going into huge amounts of detail. You will need to do some further reading and experimentation to understand each of these topics properly.
Let's start with this line in the mutation:
changedFilter = newFilterValue;
This line assigns a new value to the local variable changedFilter. That's all. As it's the last line of the mutation the net result is that it doesn't really do anything.
Presumably your intent was to update the array state.report.filters, replacing the old entry with a new entry. However, just updating a local variable isn't going to do that.
At this point you may be wondering 'If that doesn't do anything, then why is the state in my store changing?'. I'll come to that in a moment but first let me prove to you that your existing code does nothing.
Try removing the code inside setFilter completely. Just leave an empty function. Then try clicking around in the UI just like you did before. You'll find that the store state updates just the same as it did before, even though you've removed the code to update the array.
The correct way to implement that mutation would be to use findIndex to find the relevant index and then use either Vue.set or the array's splice method to update the array accordingly. That will change the item in the array. However...
This brings us back to the earlier question. Why is the state updating if the mutation does nothing?
This is because you're using the same object in multiple places. The Filter object held in the array is the same object that your UI is editing. There are no copies being taken, there is just a single object. So when you change the properties of that object inside updateOperator or updateValue this will immediately be reflected inside the store. Calling the setFilter mutation is just asking the store to replace an object with itself.
There's nothing specific to Vue about this. This is just the standard behaviour of reference types in JavaScript. It is also common with many other programming languages that don't directly expose pointers. It can be useful to learn a little about how pointers work in other languages as it will give you a better initial mental model before attempting to understand how reference types behave in JavaScript. Understanding the difference between 'by value' and 'by reference' may also be a useful starting point.
The next topic to cover is reactivity, which very much is a Vue topic.
Specifically, there are certain changes that Vue can't detect. These are usually referred to as the reactivity caveats. You can find more about them in the official documentation:
https://v2.vuejs.org/v2/guide/reactivity.html#Change-Detection-Caveats
https://v2.vuejs.org/v2/guide/list.html#Caveats
There are at least two lines in your code that violate these rules:
this.operator[0] = new Operator(operatorName);
and
this.value[0] = newValue;
You can't set array entries directly by index. The array will update but it won't trigger any reactive dependencies within Vue. Instead you need to use either Vue.set or one of the array methods, e.g. push, pop, splice, etc.. In this example you could use splice.
e.g. Using Vue.set:
Vue.set(this.value, 0, newValue);
e.g. Using splice:
this.value.splice(0, 0, newValue);
Why does all of this matters?
Well Vue will only re-render a component if its reactive dependencies have changed. They are very similar to computed properties in that regard. Here's how it works...
Vue compiles the template down to a function. That function is referred to as the render function. When rendering a component Vue calls the render function and that function returns a description of how to render the component. Any reactive properties that are touched while that function is running will be recorded as dependencies. If, at some point in the future, the value of one of those reactive properties changes then Vue will rerun the render function to generate a new rendering of that component.
There are two key points to take out of this description:
If you fall foul of one of the reactivity caveats then Vue won't know the dependency has changed, so it won't re-render the component.
The render function runs as a whole. It doesn't just target a small chunk of the template, it always runs the whole thing.
So if you change a dependency in a non-reactive way (i.e. one of the caveats) it won't trigger a rendering update. But if you subsequently update a dependency properly, Vue will detect that and will rerun the render function. When it runs it will run the whole thing, so any new values will be picked up, even if they weren't detected when they changed.
It isn't immediately clear to me which rendering dependency is causing your component to re-render. However, it only needs one of them to change in a detectable manner. Any other changes will then get pulled in incidentally when the render function runs and reads their current values.
That covers why your code isn't working. However, I would also worry about your decision to introduce a Filter class. I understand how that may be appealing if you've come from some other OO environment but it isn't typically how Vue is used. It is possible to make it work but you will need a good understanding of both JavaScript reference types and the Vue reactivity system to avoid falling through the cracks. There is no reason why using a specific class to hold your data can't be made to work but in practice it usually ends up being less maintainable than not using such a class. A more typical Vue approach would be to use simple, anonymous objects/arrays to hold the data and then for the data owner (either a component or store module) to be responsible for making any mutations to that data. Events are used to pass changes up the component hierarchy rather than callback props.
Ultimately you will need to judge whether the Filter class is justified but it is probably not what future maintainers of your code will be expecting.
I have a call in my created method which has an await.
I want to know that the results of that call are loaded so that i can conditionally show/hide things in the DOM.
Right now it looks like the DOM is being rendered before that method has completed. But I though that methods in created were called before the DOM rendered?
You're correct in assuming that the created hook runs before the component mounts. However, the lifecycle hooks are not waiting for async calls to complete. If you want to wait for that call to be completed and data to load, you can do so by using a Boolean that you set to true when your data has loaded.
Your template:
<div v-if='dataLoaded'>Now you can see me.</div>
in your vue instace
export default {
data () {
return {
dataLoaded: false
}
},
created () {
loadMyData().then(data => {
// do awesome things with data
this.dataLoaded = true
})
}
}
This way you can keep your content hidden until that call has resolved. Take care with the context when you handle the ajax response. You will want to keep this as a reference to the original vue instance, so that you can set your data correctly. Arrow functions work well for that.
I'm trying to use setPage method of vue-tables-2 library after used fetchMore from vue-apollo, But the issue its when the query get the new result, the table it's still on the first page
mounted: function(){
var ref = this
Event.$on('vue-tables.pagination', function(data) {
ref.showMore()
ref.$refs.table.setPage(data)
})
},
Vue-tables-2
I think vue-tables.pagination event is not working properly for your code.First of all you have to create one data property which will store your current page.Store number of page on which you performed your last action.Then set page to that data property.
SetPage takes in number of the page, not page data.