data: {
addItemArray: [],
}
I have initialize one array inside data and then inside methods i am added some code:
var self = this;
{
self.cacheDom.$submitItem.click(function () {
self.addItemArray.push({
‘id’: $(’#accountSearch’).data(‘id’).trim(),
‘name’: $(’#accountSearch’).val().trim(),
‘type’: $(’#accountDropdown option:selected’ ).text().trim()
});
$(’.addItemMenu’).hide();
});
}
i pushing the data into addItemArray. Then another one click function inside methods that time i need the addItemArray items. But i getting always a empty array.
Thanks
Related
I am trying to pass data to a v-select dropdown.
This of course works:
computed: {
itemDropdown() {
const menuItems = {
id: "1",
name: "Joe"
}
return menuItems;
}
}
But when I try:
computed: {
itemDropdown() {
const newArray = [...this.data.originalItems];
newArray.map(item => {
item.name = "myCoolNewName";
});
return newArray;
}
}
It mutates the original array.
I have also tried copying the object:
computed: {
itemDropdown() {
const newObj = { ...this.data };
newObj.items.map(item => {
item.name = "myCoolNewName";
});
return newObj;
}
}
Not sure what I’m missing, but wondering if there is a work around. Thanks for any help :slight_smile:
You are using the map array method wrong.
The first thing you need to know, is that the map method returns a new array, so you have to either return the result of your map function or save it in a variable, otherwise you will just be looping through your array without ever saving it anywhere.
Another thing is about how you use the map method.
Here I have made an example of how it should work with your code:
computed: {
itemDropdown() {
return this.data.originalItems.map(item => {
return {
name: "myCoolNewName"
}
});
}
}
The big difference you should notice, is that inside the map function, we have to return what we want each object to look like, after we have gone through it. We want it to give us the object back, but make some changes to it, so we have to actually return an object and change what we want in that.
What you were doing before, was refering to the item in the old array, and assigning it a new value, instead of returning a new object with your changes.
You can read about the array.map method here
Hope that makes sense :)
I am trying to send an array containing arrays which in turn contains objects to one component from another, but the content from the array seems to be empty in the child component.
I have tried sending the data as a String using JSON.Stringify() and also as an array
My parent component:
data: function(){
return{
myLineItems : []
}
},
created(){
this.CreateLineItems();
},
methods:{
CreateLineItems(){
let myArrayData = [[{"title":"Title1","value":2768.88}],[{"title":"Title2","value":9}],[{"title":"Title3","value":53.61},{"title":"Title4","value":888.77},{"title":"Title5","value":1206.11},{"title":"Title6","value":162.5}]]
this.myLineItems = myArrayData;
}
}
My parent component's template:
/*
template: `<div><InvoiceChart v-bind:lineItems="myLineItems"></InvoiceChart></div>`
My child component:
const ChildComponent= {
props: {
lineItems: {
type: Array
}
},
mounted() {
console.log(this.lineItems);
}
};
The parent component is created as so (inside a method of our main component):
var ComponentClass = Vue.extend(InvoiceDetails);
var instance = new ComponentClass({
propsData: { invoiceid: invoiceId }
});
instance.$mount();
var elem = this.$refs['details-' + invoiceId];
elem[0].innerHTML = "";
elem[0].appendChild(instance.$el);
If I try to do a console.log(this) inside the childcomponent, I can see the correct array data exist on the lineItems property..but i can't seem to access it.
I have just started using VueJS so I haven't quite gotten a hang of the dataflow here yet, though I've tried reading the documentation as well as similar cases here on stackoverflow to no avail.
Expected result: using this.lineItems should be a populated array of my values sent from the parent.
Actual results: this.lineItems is an empty Array
Edit: The problem seemed to be related to how I created my parent component:
var ComponentClass = Vue.extend(InvoiceDetails);
var instance = new ComponentClass({
propsData: { invoiceid: invoiceId }
});
instance.$mount();
var elem = this.$refs['details-' + invoiceId];
elem[0].innerHTML = "";
elem[0].appendChild(instance.$el);
Changing this to a regular custom vue component fixed the issue
Code - https://codesandbox.io/s/znl2yy478p
You can print your object through function JSON.stringify() - in this case all functions will be omitted and only values will be printed.
Everything looks good in your code.
The issue is the property is not correctly getting passed down, and the default property is being used.
Update the way you instantiate the top level component.
Try as below =>
const ChildComponent= {
props: {
lineItems: {
type: Array
}
},
mounted() {
console.log(this.lineItems);
}
};
My code like this:
<tempalte>
<div>{{contents}}</div>
</tempalte>
<script>
{
//...something
data: function() {
return { contents: null }
},
methods: {
test() {
console.log(this.contents)
}
},
created () {
// do something...
this.contents = someValue
this.test()
}
}
</script>
And when created excuted then call test methods, the print result is old value null.
But the {{contents}} is the new Value.
How can I get new value of data in methods after created assign new value and call the methods ?
I has already fixed it. If I call methods in updated (), it can work.
If you want to know the reasons, you can read this post:
https://v2.vuejs.org/v2/guide/reactivity.html
I had an API call to the backend and based on the returned data, I set the reactive data dynamically:
let data = {
quantity: [],
tickets: []
}
api.default.fetch()
.then(function (tickets) {
data.tickets = tickets
tickets.forEach(ticket => {
data.quantity[ticket.id] = 0
})
})
Based on this flow, how can I set watcher for all reactive elements in quantity array dynamically as well?
You can create a computed property, where you can stringify the quantity array, and then set a watcher on this computed property. Code will look something like following:
computed: {
quantityString: function () {
return JSON.stringify(this.quantity)
}
}
watch: {
// whenever question changes, this function will run
quantityString: function (newQuantity) {
var newQuantity = JSON.parse(newQuantity)
//Your relevant code
}
}
Using the [] operator to change a value in an array won't let vue detect the change, use splice instead.
I need to check variable rasters_previews_list for changing. Here is my code:
var userContent = Vue.extend({
template: '<p>Some template</p>',
data: function () {
return {
rasters_previews_list: []
}
},
watch: {
'rasters_previews_list': function(value, mutation) {
console.log("Value changed");
}
}
});
But In console I do not see Value changed when it got new data.
Data changing function:
map.on('draw:created', function (e) {
//...
Vue.http.post('/dbdata', DataBody).then((response) => {
userContent.rasters_previews_list = response; // putting JSON answer to Component data in userContent
console.log(response);
}, (response) => {
console.log("Can't get list rasters metadata from DB. Server error: ", response.status)
});
I change value in map.on('draw:created', function (e) (Leaflet JS). I see console.log output, so seems data is changing.
If you want to change the value of an array you will have to use the special Array extension methods Vue.set and Vue.delete.
Due to limitations of JavaScript, Vue cannot detect the following changes to an Array:
When you directly set an item with the index, e.g. vm.items[0] = {};
When you modify the length of the Array, e.g. vm.items.length = 0.
https://vuejs.org/api/#Vue-set
This problem is also mentioned in the common gotchas
When you modify an Array by directly setting an index (e.g. arr[0] = val) or modifying its length property. Similarly, Vue.js cannot pickup these changes. Always modify arrays by using an Array instance method, or replacing it entirely. Vue provides a convenience method arr.$set(index, value) which is just syntax sugar for arr.splice(index, 1, value).