I have created a form which allows the user to add additional text-inputs by clicking a button. The FormControls behind these inputs are stored in a FormArray inside of a FormGroup.
I want to provide a default value for these inputs, that is going to be submitted if they are pristine. If the user changes the value of the input, which changes it to dirty, I do not want the default value to be submitted or displayed.
I currently am displaying the inputs like this, as the placeholder attribute does exactly what I want, displaying the default name, only if the input has not been changed.
<div
formArrayName="names"
*ngFor="let server of names.controls; let i = index; trackBy:trackByFn">
<span>{{ i + 1 }}</span>
<input
type="text"
formControlName="{{i}}"
placeholder="{{defaultName}}">
</div>
To validate the names I have created the following validation function:
export function validateServerName(form: FormGroup): ValidationErrors | null {
const names: string[] = form.value[CREATE_FORM_KEY_NAMES];
for (const name of names) {
if (name.trim() === '') {
return {
invalidName: true
};
}
}
return null;
}
Here I am having trouble figuring out if the element is dirty or pristine, as form.value[key] only returns a string array, not an array of the FormControls.
I am looking for either an easier way to do what I am trying to achieve, or a way to validate the form properly.
you can check the control status using
if touched is true then its dirty
this.form.get('controlname').touched
and for pristine you can check like
this.form.get('controlname').pristine
UPDATE
for form array it will be something like
let val = this.user.get('<FormArray>') as FormArray;
console.log(val.at(index));
you can now use pristine and touched on this variable
Related
I have an array of objects that includes an element with an object and I'm looking to display the name of the object on a selectable dropdown using ng-select. I can console log everything as expected, however when I try to display the data I am only able to show [object, object]. The correct number of objects.
HTML -
<ng-select
[searchable]="false"
bindValue="id"
bindLabel="medications.items"
[items]="selected"
[(ngModel)]="serviceUsersMedication">
</ng-select>
TS -
onSelect({selected}) {
this.selected = selected;
const filteredMeds = this.selected.filter(item => {
return item.medications;
});
this.serviceUsersMedication = filteredMeds.map(item => {
return item.medications;
});
console.log('Selected:');
console.log(this.selected);
}
You're using the same variable for [items] (the collection ng-select uses to display the options) as for [(ngModel)] (used for storing/displaying the SELECTED (1) item).
You have to split this:
[items] should refer to the collection
[(ngModel]) should refer to your selected item.
Your ng-select should look like this:
<ng-select
[searchable]="false"
bindValue="id"
bindLabel="name"
[items]="medications.items"
[(ngModel)]="selected">
</ng-select>
Assuming you have a name attribute in the items array of medication, else change it to the attribute that makes sense to show.. selected is already containing the selected item, no need to filter for that.
Also assuming you're using ng-select from #ng-select/ng-select
In Angular, how to use *ngIf to check whether a JSON value includes a certain string, and then show them a certain URL ? In my case I have a object name called campaigns.description which has a value that includes a description. I want to see whether a given string, for example "one beam" is included in that description and show an URL based on that.
So not the way that the value equals a certain string, but the text that is held within the value includes a certain string.
You can use indexof() function to check the existence of some substring inside a string. This function returns '-1' if the substring is not present in the string.
<label *ngIf="campaigns.description.indexOf('One Beam') != -1 ? true : false">{{urlToShow}}</label>
You could generally use indexOf to check whether a string contains a sub-string.
console.log("Sample string".indexOf('string'));
console.log("Sample string".indexOf('not'));
The Angular part:
Trivial (not recommended)
Trivial solution is to check directly in the *ngIf condition
<div *ngIf="campaigns.description.indexOf('one beam') !== -1; else other">
<!-- contains the sub-string -->
</div>
<ng-template #other>
<!-- does not contain the sub-string -->
</ng-template>
However binding a function to *ngIf directive with default change detection strategy would trigger the function for each change detection cycle. It might lead to performance issues.
Additional property (recommended)
You could introduce additional property to hold the result of the condition in the controller and use it in the template.
Controller (*.ts)
// I assume `campaigns` is initialized in a subscription
ngOnInit() {
someObservable.subscription(
(res: any) => {
this.campaigns = {
...res,
subString: res.description.indexOf('one beam') !== -1
}
},
(error: any) => { }
);
}
Template (*.html)
<div *ngIf="campaigns?.subString; else other">
<!-- contains the sub-string -->
</div>
<ng-template #other>
<!-- does not contain the sub-string -->
</ng-template>
I am in the following situation and have the following problems.
I am developing an application that reads data from a .json file. I store this data in rows. Now the .json files can be different and therefore I have to cover every case (there are many cases). If a tag is not present in the .json, this row should not be displayed.
Now it can happen that I have covered a case which searches for data.test.person but data.test is not present in the JSON.
A case could look like this:
<TestAntragsdatenAbschnitt
title={"Test"}
value={data.test}>
<TestAntragsdatenRow
label1={"Person"}
value1={data.test.person}
/>
</TestAntragsdatenAbschnitt>
This is my component.
export default class TestAntragsdatenAbschnitt extends React.Component {
value;
title;
render() {
this.value = this.props.value;
this.title = this.props.title;
return (
<>
<h4 className={"antragsdatenAbschnitt"}>
{checkAbschnitt(this.title, this.value)}
</h4>
{this.value != null &&
this.props.children
}
</>
);
}
}
With the query this.value != null && I have tried to work around the error.
The error I get: TypeError: Cannot read property 'person' of undefined
My question now is, how can I query JSON tags if they exist, if so the rows should be checked. If not all rows with this tag should be skipped.
Object.keys(data).includes('test')
can be a way of checking if json object has the property.
There are a lot of other ways as well. You can also try:
value1={data.test ? data.test.person : 'error'}
kind of approach for safe null-checking
There are a couple of things wrong with your code, but let's try to unpack everything:
You're passing two props, title and value to your component named TestAntragsdatenAbschnitt. This you should receive in props, and therefore there's no need for you to store them in fields (this.value = this.props.value) for example.
Rather, just do this in the render function:
const {title, value, children} = this.props;
And now you don't need to use this.title and this.value, but just title and value.
OK we got that out of the way, now let's figure out why your optional key isn't working:
Now you should be rendering your children like this:
{children}
Now you need to conditionally render particular rows, and this shouldn't be done here in this component at all. This should be done in the component that's rendering TestAntragsdatenAbschnitt (first component you wrote in the post).
So you'd do something like this:
<TestAntragsdatenAbschnitt
title={"Test"}
value={data.test}>
{data && data.test && data.test.person ? (
<TestAntragsdatenRow
label1={"Person"}
value1={data.test.person}
/>
) : (
<p>data.test.person is not valid</p>
)}
</TestAntragsdatenAbschnitt>
As you can see, I check with the ternary operator if data.test.person is not null, if it isn't then just render the row, if not then just do something else you'd like.
You could do this in other component, but this way it's way cleaner in my opinion.
I have a service which returns a JSON of type array[obj1{name, usage, id}, obj2{name, usage, id}] on HTML page I am creating a form with form field = name and it is pre-populated with value = usage. Ex: if there are 2 objects inside array where name1=a usage1=1 and name2=b and usage2=2, 2 form fields will be created. Form field names will be name1 and name2 and will be filled already with usage1 and usage2 value respectively. I am doing this with this code:
<form>
<div class="form-row">
<div class="form-group" *ngFor="let item of items">
<label>{{item.name}}</label>
<input type="number" min="0" [id]="item.name" [name]="item.name" class="form-control" [(ngModel)]="item.usage">
</div>
</div>
</form>
It is working fine. Now suppose user changes the value for usage1 and usage2. On submit button I have to create a json object in typescript and send it in the API. I am facing issues to create the JSON object. I have tried:
onSubmit{
this.changedValues = this.items.usage;
console.log(this.changedValues);
}
But console.log return undefined. Json object I am expecting should be something of they type:
changedValues[{upadatedUsage1, id1},{updatedUsage2, id2}]
How can I create a json object dynamically and also how can I send the correct id with the correct updated usage value. Thank you
The reason for undefined value is that, items is an array and hence doesn't have the property usage
onSubmit {
this.changedValues = this.items;
console.log(this.changedValues);
}
This should give the array with updated values.
I want to allow a user to provide a list of one-word attributes without parameter values. For example,
<container row crosscenter wrap spacearound ...>
which results in something like this in container.html
<div [ngClass]="{ 'flexDisplay': true, 'directionRow': isRow, 'directionCol': isCol, 'contentSpaceAround': isSpaceAround}" ...>
What I'm missing is how to set
#Input('row') isRow = false;
to true if 'row' was present in the container line.
Any ideas?
Thanks in advance.
Yogi
This can be handled in ngOnChanges. The value can be assigned either back to input property or to some object that will be passed to ngClass
ngOnChanges(changes: SimpleChanges) {
if ('foo' in changes) {
this.options.foo = true;
}
}
Since there's no way how inputs can become unassigned, there's no reason to provide bindings for them. #Attribute can be used instead:
constructor(#Attribute('foo') public foo: boolean|null) {
this.foo = (foo != null);
}
Using attributes for regular options isn't a good decision, design-wise. This prevents from setting them dynamically. Instead, it is always preferable to accept options input. If all options are supposed to be flags, it can be a string input that will be split and processed in ngOnChanges, like:
<container options="row crosscenter wrap spacearound">
or
<container [options]="'row crosscenter wrap spacearound'">
I think the answer to my question is to create directives for each of the "one-word" tags (attributes) I want to use.
:-)