Skip watcher in vueJS - vue.js

I have a form for updating document entity.
The document entity consists of list of employees (which is an array of objects) and each employee has a post which is just a string.
I have a dropdown (kind of wrapper for vue-multiselect) which accepts the array of employees and syncs selected employee to a selectedEmployee variable in data().
And also I have a watcher for selectedEmployee which sets the post input automatically when an employee is selected in the dropdown.
So, when creating a document in the form everything's fine, however, when I update the document, then I fetch existing document from server, set selectedEmployee and set employee's post. But, the document also keeps employee's post, so the first time when I open document's form in order to update it, I don't want to automatically update document's post. I want it to be updated only when user actually selects employee himself.
But the watcher gets called the first time too.
So, imagine we have John Doe and his a manager. When I create the document, I change his post to designer. Then, I open up the document form in order to update it, and I should see that for this specific document John Doe's post is "designer", but the watcher gets called and returns the post to manager.
I tried to make a fake variable in data(), like doneFetching, but it works only if I update this var directly in watcher, which looks quite dangerous, plus, in other entities I have many different kinds of selected employees, so making tons of fake flags is not an option.
Here is real code sample (employee = representative in my case):
selectedApproveRepresentative(representative) {
if (!representative) {
this.memoData.approve_representative_id = null
return
}
this.memoData.approve_representative_id = representative.id
// Here is temporary solution, but I have many watchers for many different kinds of employees. If I move the doneFetching flag after I initialized the form, it'll be set to true, and only after that the watcher will be called
if (this.mode === 'update' && !this.doneFetching) {
this.doneFetching = true
return
}
// In normal case a representative might have or have not post, so depending on this case we set it to be empty or filled. But this should not be called the first time I open the form
this.memoData.approve_representative_post_dative_case =
representative.post_dative_case ?
representative.post_dative_case : ''
},
Here is where I initialize data:
created() {
if (this.memo) {
this.memoData = _.cloneDeep(this.memo)
this.selectedApproveRepresentative = _.cloneDeep(this.memo.approve_representative)
}
},

as I understood, your problem is the watcher executed when you init the component. Have you tried setting the immediate property of the watcher to false?
Not everybody knows that the watchers can be defined in different ways.
The simple one that everybody know
watchers: {
propertyToWatch() { //code... }
}
Passing the name of a function as 'string'
watchers: {
propertyToWatch: 'nameOfAfunctionDefinedInMethodsSection'
}
The object declaration
This one is the most descriptive way of declaring a watcher. You write it as an object with a handler property (it can be the name of a function passed as string as above), and other properties like deep to watch nested properties of an object, or in your case immediate which tells to the watcher if the should run immediately when the component is mounted.
watchers: {
propertyToWatch: {
immediate: false,
handler: function() { //code.. }
}
}

Related

bind dynamically to this vuejs

Hey guys I have the following function its working ok but I think it could be better.
methods: {
onFileChange(e, filedName) {
console.log(e.target.files);
console.log(filedName);
const file = e.target.files[0];
const fileToCheck=document.getElementById(filedName);
console.log(fileToCheck);
if(filedName=='thumbnail1'){
if(fileToCheck.value!=''){
this.thumbnail1 = fileToCheck;
this.thumbnail1Url= URL.createObjectURL(file);
} else {
this.thumbnail1=null;
this.thumbnail1Url=null;
}
}
if(filedName=='thumbnail2'){
if(fileToCheck.value!=''){
console.log(fileToCheck);
this.thumbnail2=fileToCheck;
this.thumbnail2Url = URL.createObjectURL(file);
} else {this.thumbnail2=fileToCheck; this.thumbnail2Url=null;}
}
},
Instead of checking the value for
if(fieldName == "something"){
this.something = URL.createObjectURL(file)
}
I would simply pass in a string of the fieldName and bind to it dynamically by just typing this.fieldName (filedName could equal thumbnail1 or thumbnail2 or chicken for all I care I just want to be able to pass in the name of the data atrribute and bind to it that way) but when ever I do this it doesn't work. Any help here would be great.
It's not completely clear to me what you want to accomplish, but I think you're asking about creating a dynamic data property for a view component. If that's the case, there are a couple of things to consider.
First, the example you cite, this.fieldName is not correct JavaScript syntax if fieldName is a string that contains a property name. The correct version is this[fieldName].
Note, though, that you can't simply define a new data property for a Vue component by setting it to a value. That's a limitation of JavaScript that's described in the Vue documentation. If data[fieldName] is an existing property that's defined in the component's data object, then you'll be okay. Even if you don't know the value of the property, you can initialize it, for example, with a value of null and then update the value in your method. Otherwise, you'll need to add the property to an existing non-root-level property as the documentation explains.

My Vuex getter is not getting automatically updated.. how I can debug it?

I'm using Vuex with a getter that filters a lot of data and then some components present it to the user grouped by status. The user can increment the visible count of elements per status by 5. How many items are visible currently is on the Vuex store and a getter uses this to create a "View object".
When I update this visibility object the getter is no rerun so something in the dependency tracking went south. I'm not adding or deleteing properties, still I'm using Vue.set(...) just to be sure.
This is the mutation that increments the visible amount of items for a status:
viewMore(state, status) {
console.log('viewMore')
const current = state.visibility.statuses[status]
Vue.set(state.visibility.statuses, status, current + 5)
}
This mutation is running well and I can see in the developer tools how the visibility increments reactively with every commit. Now here is the getter that depends on this data:
visibleProspects(state, getters) {
console.log('visibleProspects')
let result = {}
for (const status in getters.sourceData) {
if (!result[status]) {
result[status] = { prospects: [] }
}
getters.sourceData[status].forEach(function(prospect) {
if (result[status].prospects.length < state.visibility.statuses[status])
result[status].prospects.push(prospect)
})
}
return result
}
What this does is traverses a complex getter named sourceData (not shown here for brevity) and then depending on how many visible items there are it returns a new structure with that maximum in an array. visibleProspects is then used by my components and everything runs fine the first time or if a update the data that sourceData computes (e.g adding / editing / deleting a prospect).. but no matter what I do modifying state.visibility.statuses is not forcing visibleProspects to recompute.
How can I debug this?
You can make deep copy to make it reactive (using JSON.parse(JSON.stringify())
viewMore(state, status) {
console.log('viewMore')
const current = state.visibility.statuses[status]
state.visibility.statuses[status] = current + 5
state.visibility = JSON.parse(JSON.stringify(state.visibility))
}
#ittus 's answer should work. But the clone operation would be heavy if your state is big.
alternatively, you may try using Vue.set on the root state state.visibility instead. This should make the reactivity works as expected.
Vue.set(state.visibility, 'statuses', {
...state.visibility.statuses,
[status]: current + 5
})

How to 'watch' newly created rows in local storage in VueJs?

I am working to create a grid like component in VueJs. You can see the JSFiddle here: https://jsfiddle.net/masade/nrb9f4j2/
In the above fiddle the <datacell> component is used to allow inline edit for any cell.
I am 'watch'-ing changes to the rows and saving them in local storage
A newly created row is being pushed to parent object by this.$parent.unshift(newrow) in the <addrow> component
The problem is when I add a new row, though it is being added to the rows local storage it is not being watched for changes
Steps to replicate the issue (on JS fiddle):
Click on Add Row and enter a name to add
Once the row is added, click on the second column (year) and update it
Any changes to newly added row is not being updated
However if you refresh the page, and modify the same again, I am able to update it again.
Please help me understand if I am doing something wrong
You stumbled into one of the change detection caveats in Vue. Vue cannot detect when you have added a property to an object using the index of that object.
You define newrow like this:
data: function(){
return {
newrow : {}
}
},
which means that newrow has no properties. After that, you always add properties to newrow using an index, like here:
this.$parent.cols.map(function(col,index){
if(typeof newrow[col.m] == "undefined")
newrow[col.m] = "";
})
This means that Vue doesn't know about any of the properties you just added.
I added a method to your fiddle called makeNewRow which adds the properties you need to newrow correctly using the $set method.
makeNewRow(){
this.newrow = {};
this.$parent.cols.map((col,index) => this.$set(this.newrow, col.m, null))
},
Then I call it in mounted and in your addRow method. This fixes your bug. Here is the updated fiddle.
Note: there was an additional bug in your code that I fixed. If someone opened your app and did not previously have grid-vue-local in their local storage, then the uid for gridStorage would be zero, and the first row they added would have the id 0. To fix this I simply added
save: function (rows) {
gridStorage.uid = rows.length
localStorage.setItem(STORAGE_KEY, JSON.stringify(rows))
}
data(){
return{
items:localStorage.fetch()
}
}
watch:{
items:{
handler:function(items){
localStorage.save(items);
},
deep:true
}
}
you can save in items,and watch items,if the items has changed,it will updata

How can I observe a property rather than the object it points to with WinJS?

Hopefully I'm describing this correctly. I'm making a windows store app and I have the following setup
WinJS.Namespace.define("Model",
{
WorkOrders: new WinJS.Binding.List(),
selectedWorkOrder: {}
});
WinJS.Namespace.define("ViewModel",
{
WorkOrders: Model.WorkOrders,
selectedWorkOrder: Model.selectedWorkOrder
})
When the page is loaded an ajax request populates a list of WorkOrders, after they're populated a user can select one, at which point Model.selectedWorkOrder is set to one of the objects in Model.WorkOrder.
I want ViewModel.selectedWorkOrder to reflect whatever Model.selectedWorkOrder is, but it seems to bind only to the originally empty object, how can I make it bind to that property (even if the object changes, like a pointer).
I'm doing something like this to set the selectedWorkOrder
Model.selectedWorkOrder = results[i];
Thanks!
Not sure if I understand your question correctly.
What you're looking for is some kind of event to get in ViewModel.selectedWorkOrder whatever Model.selectedWorkOrder has, right?
If that's the case you could try RxJS-WinJS (which I'm honestly not too familiar with) or you could just make ViewModel.selectedWorkOrder a method that gets and returns whatever Model.selectedWorkOrder has at any given time.
Something like this:
WinJS.Namespace.define("Model",
{
WorkOrders: new WinJS.Binding.List(),
selectedWorkOrder: {}
});
var _getWorkItem = function(){
return Model.selectedWorkItem;
}
WinJS.Namespace.define("ViewModel",
{
WorkOrders: Model.WorkOrders,
selectedWorkOrder: _getWorkItem
})

extjs 4.1 how to reset the itemselector

I am using extjs 4.1.1a for developing some application.
I had a form consisting of two combo-boxes and an item-selector.
Based on the value selected in first combo-box , the itemselector will load its data from database. This is working fine.
My problem is, if i reselect the first combo-box the new data will be displayed in itemselector along with previous data displayed in itemseletor .That is previous data displayed in itemselector will remain there itself.
for example: name "test1" consists of ids 801,2088,5000. on selecting test1 in firstcombobox itemselector must show output as below.
and if "test2" consists of ids 6090,5040. on selecting test2 in firstcombobox itemselector must show output as below.
problem is. for first time if i select "test1" from firstcombobox , output will come as expected. if i reselect "test2" from firstcombobox , output will come as below.
as you can see, previous data displayed (marked in red rectagle) remains there itself with new data displayed (marked with green rectangle).
I want for every reselection of first combobox, previously displayed data in itemselector to be erased before printing new data on itemselector.
How can I reset the itemselector for every reselection of first combobox?
You should remove all items from the store of the itemselector by the removeAll command. After that you should load the store of the itemselector.
itemselector.store.removeAll();
itemselector.store.load();
Any solutions above solve my problem.
i found solution from Sencha Forum.
https://www.sencha.com/forum/showthread.php?142276-closed-Ext-JS-4.0.2a-itemselector-not-reloading-the-store
in the itemselector.js file, change the line marked below.
populateFromStore: function(store) {
var fromStore = this.fromField.store;
// Flag set when the fromStore has been loaded
this.fromStorePopulated = true;
// THIS LINE BELOW MUST BE CHANGED!!!!!!!!!!!!
fromStore.loadData(store.getRange()); //fromStore.add(store.getRange());
// setValue waits for the from Store to be loaded
fromStore.fireEvent('load', fromStore);
},
You need to insert...
this.reset();
at the head of the function that is inserting the data.
As an example...
Ext.override( Ext.ux.ItemSelector, {
setValue: function(val) {
this.reset();
if (!val) return;
val = val instanceof Array ? val : val.split(this.delimiter);
var rec, i, id;
for (i = 0; i < val.length; i++) {
var vf = this.fromMultiselect.valueField;
id = val[i];
idx = this.toMultiselect.view.store.findBy(function(record){
return record.data[vf] == id;
});
if (idx != -1) continue;
idx = this.fromMultiselect.view.store.findBy(function(record){
return record.data[vf] == id;
});
rec = this.fromMultiselect.view.store.getAt(idx);
if (rec) {
this.toMultiselect.view.store.add(rec);
this.fromMultiselect.view.store.remove(rec);
}
}
}
});
are u got it?
when u select that combobox frist stoe of item selector is null after store load with ur pass the para meters
for example
store.load(null),
store.proxey.url='jso.php?id='+combobox.getrawvalue(),
store.load();
like that so when ur select a value in ur combobox that time ur used a listeners to ur combobox in that listners ur used above code , select ur some value in combobox that time frist store is get null after ur pass some values to json.php then store load with responce so that time old data is remove and new data load in that store
if u post ur code i will give correct code
I ran into the same issue with ExtJS 4.2.1. I got it to work by calling reload() on the data store and then setValue() with an empty string on the item selector in the data store's reload() callback.
Ext.create("Ext.form.field.ComboBox", {
// Other properties removed for brevity
listeners: {
change: function(field, newValue, oldValue, eOpts) {
Ext.getStore("ExampleStore").reload({
callback: function() {
Ext.getCmp("ExampleItemSelector").setValue("");
}
});
}
}
});
Ext.create("Ext.data.Store", {
storeId: "ExampleStore",
// Other properties removed for brevity
});
Ext.create("Ext.form.FormPanel", {
// Other properties removed for brevity
items:[{
xtype: "itemselector",
id: "ExampleItemSelector",
// Other properties removed for brevity
}]
});
For any folks that are curious, I'm fairly convinced there's a bug in the item selector's populateFromStore() function. When the function is called, it blindly adds all of the values from the bound store (store) to the internal store (fromStore). I suspect there should be a call to fromStore.removeAll() prior to the call to fromStore.add(). Here's the relevant code from ItemSelector.js.
populateFromStore: function(store) {
var fromStore = this.fromField.store;
// Flag set when the fromStore has been loaded
this.fromStorePopulated = true;
fromStore.add(store.getRange());
// setValue waits for the from Store to be loaded
fromStore.fireEvent('load', fromStore);
},
EDIT 12/18/2013
If you've configured any callback events on the item selector (e.g. change), you may want to disable the events temporarily when you call setValue(""). For example:
var selector = Ext.getCmp("ExampleItemSelector");
selector.suspendEvents();
selector.setValue("");
selector.resumeEvents();
I had the same problem and finally I decided to modify the extjs source code, not considering it a big issue as extjs itself its saying in the start of the file
Note that this control will most likely remain as an example, and not as a core Ext form
control. However, the API will be changing in a future release and so should not yet be
treated as a final, stable API at this time.
Based on that, as jstricker guessed (and sadly I didn't read and took me a while to arrive to the same conclusion), adding fromStore.removeAll() before fromStore.add() solves the problem.
Outside of the problem (but I think it can be interesting as well), additionally, I also added listConfig: me.listConfig in the MultiSelect configuration (inside createList), that way it's possible to format each item additional options (such as images, etc.) setting in the 'itemselector' the option listConfig as it's explained in the (irrealistic) documentation.
Need to reset the store used in ItemSelector that can be done by setting Empty object like below. Also need to call clearValue() method of ItemSelector component.
store.setData({});
ItemSelectorComponent.clearValue();