Given an observable like:
import "./styles.css";
import { observable } from "mobx";
const a = observable({
firstName: {
value: "a"
},
lastName: {
value: "b",
foo() {
// can I access firstName from `this`?
return this.value;
}
}
})
Something like getParent(this).firstName.value?
You can't but that has nothing to do with mobx. This is just how Javascript works.
As you know firstName and lastName are completely separated objects, that happen to be contained in the same parent object. You can't go up in object references.
Related
I have the below code in Vue3:
data: function() {
return {
testData:[],
}
},
mounted() {
var testObj = {
name: 'aniket',
lastname: 'mahadik'
}
for (let index = 0; index < 3; index++) {
this.testData.push(testObj);
}
},
methods: {
updateLastName: function(key) {
this.testData[key].lastname = 'kirve';
}
}
When I call updateLastName(1) to update the lastname of only the second element, it's updating the lastname of all the elements.
I tried several ways but found no desired result.
Can someone point out to me what is going wrong here?
It is because you are pushing the reference to the same object in the array so when you update any item in the array you are instead updating every item since it reference the same object.
Either push by cloning the object :
testData.value.push({...testObj})
Or put the definition in the push
testData.value.push({ name: 'aniket', lastname: 'mahadik' })
Is JavaScript a pass-by-reference or pass-by-value language?
Look at the image below and please explain where should I use computed instead of methods and vice versa? It confuses me.
As a rule of thumb: a computed is a simple getter (though they can be setters, but that's not something you'd typically use) that is dependent on one or more properties. It'll update automatically when those properties change. You cannot pass it parameters. You would use a method when you need to pass a parameter and/or need to perform an action or mutation.
data() {
firstName: 'Bert',
lastName: 'Ernie'
},
computed: {
fullName() {
return `${this.firstName} ${this.lastName}`;
}
}
This will return "Bert Ernie" and will update automatically when either firstName or lastName change.
Now if you need to change something, or for example select something from a list using a parameter, you would use a method.
data() {
users: [
{ id: 1, name: 'Bert' }.
{ id: 2, name: 'Ernie' }
]
},
methods: {
getUser(userid) {
return this.users.find(user => user.id === userid);
},
setUserName(userid, newName) {
const user = this.users.find(user => user.id === userid);
if (user) {
user.name = newName;
}
}
}
I want to validate an object array inside nested object array
FormData:Array[8]
0:Object
group:Object
id:1
cards:Array[8]
0:Object
id:2253
service:Object
name:"Service Name"
...
I need to validate from service only the name
I try with something like this, but no success...
validations() {
return {
FormData: {
$each: {
group: {
cards: {
$each: {
service: {
name: {
required
}
}
}
}
}
}
}
}
}
Seems like the $each is not working as i want to, what im doing wrong how can i get to correct nested object with $each ?
What is the best approach for accessing a single nested record in Ember?
The JSON response which we are trying to manipulate looks gets returned as the following: (the attribute being targeted is the tradeIdentifier property)
trade:
tradeIdentifier:"83f3f561-62af-11e7-958b-028c04d7e8f9"
tradeName:"Plumber"
userEmail:"test#gmail.com"
The project-user model looks partially like:
email: attr('string'),
trade:attr(),
tradeId: attr(),
The project-user serializer looks partially like:
export default UndefinedOmitted.extend(EmbeddedRecordsMixin, {
primaryKey: 'userRoleId',
attrs: {
'email': { key: 'userEmail' },
'trade': { key: 'trade' },
'tradeId': { key: 'tradeIdentifier' },
},
});
The trade attr here is a placeholder to make sure that the data was accessible.
I would like to be able to access the tradeIdentifier without having to do the following in the component:
const trade = get(formRole, 'trade');
if (trade) {
set(formProps, 'tradeId', trade.tradeIdentifier);
}
Have tested creating a trade-id transform (referenced via tradeId: attr('trade-id')), however to no avail.
export default Transform.extend({
deserialize(val) {
const trade = val;
const tradeId = val.tradeIdentifier;
return tradeId;
},
serialize(val) {
return val;
},
});
Can anyone suggest where I'm going wrong?
A transform seems a bit overkill for what I'm trying to achieve here, however it does the job. Managed to get it working by modifying the following:
In serializers/project-user.js:
'tradeId': { key: 'trade' },
Note that this references the property in the payload to transform, not the property being targeted (which was my mistake).
In models/project-user.js:
tradeId: attr('trade-id'),
Attribute references the transform.
In transform/trade-id.js:
export default Transform.extend({
deserialize(val) {
let tradeId = val
if (tradeId) {
tradeId = val.tradeIdentifier;
}
return tradeId;
},
serialize(val) {
return val;
},
});
If there's a simpler solution outside of transforms, I would still be open to suggestions.
I am trying to get the array values from
"validateBeforeSubmit" function to "saveForm" function. But I am
getting values of "undefined" in "arrlength". Please help me to solve.
This my code in vue.js
export default {
name: '',
data() {
return {}
},
ready: function() {
this.validateBeforeSubmit()
this.saveForm();
},
methods: {
validateBeforeSubmit() {
var fieldsVal = new Array();
var firstName = document.getElementById('firstName').value
var lastName = document.getElementById('lastName').value
var designation = document.getElementById('designation').value
if (firstName != "" && lastName != "" && designation != "") {
fieldsVal.push(firstName);
fieldsVal.push(lastName);
fieldsVal.push(designation);
return fieldsVal;
} else {
fieldsVal.length = 0;
return fieldsVal;
}
return fieldsVal;
},
saveForm() {
var fieldsValArray = this.validateBeforeSubmit();
var arrLength = fieldsValArray.length;
}
}
}
I can see multiple issues in your code:
1) Don't apply jQuery-like approach for getting input values. Use v-model instead. This will simplify your code
<template>
<input v-model="form.firstName" type="text"/>
</template>
<script>
export default {
data: {
form: {
firstName: '',
}
},
methods: {
validateBeforeSubmit() {
// take `firstName` directly from `data` not need for `getElementById`
const firstName = this.form.firstName;
}
},
}
</script>
2) Remove validateBeforeSubmit and saveForm from ready. Ready hook is obsolete in vue#2. And also it makes no sense. It's better to call it on form #submit.
3) It's better to create array using [] syntax instead of new Array()
Why never use new Array in Javascript
4) Always provide name for your component for easier debug
export default {
name: 'ValidationForm',
}
5) I don't know where was an issue but it works. Check this link below. I have updated your code. Try to submit form and check the console:
https://codesandbox.io/s/w6jl619qr5?expanddevtools=1&module=%2Fsrc%2Fcomponents%2FForm.vue