I have an array of items that need to be displayed based on roles. I need the first value which will fulfil the ngIf condition.
I am adding my code below:
My Array(kind of how it will originally look):
parentTabList = [
{
name: 'abc',
label: 'abc',
icon : 'question_answer',
role : ['vend_perm','vend_temp','vend_subs']
},
{
name: 'xyz',
label: 'xyz',
icon : 'question_answer',
role : ['vend_perm','vend_subs']
}
]
My Html: -
<ng-container *ngFor="let form of parentTabList let i = index">
<li *ngIf="form.role.includes(userRole)">
<a (click)="methodName(form)">
{{form.label}}
</a>
</li>
</ng-container>
UserRole is a string value that I get when a user logs-in.
I need to add a ngClass to the anchor tag if it is the first anchor to be displayed.
(I am a noob at StackOverflow, please let me know if any more explanation is required).
You can identify first element of the array with index.
But as per my understanding you need filter this array with roles and then apply ngClass to first element from filtered list.
So add method to return filtered array with respect to roles
In Template:
filterParentTabList(parentList: any) {
return parentList.filter(form => form.role.includes(this.userRole));
}
In View:
<ng-container *ngFor="let form of filterParentTabList(parentTabList); let i = index">
<li>
<a [ngClass]="{ 'addYourClaaName': i === 0 }" (click)="methodName(form)">
{{form.label}}
</a>
</li>
</ng-container>
Happy Coding.. :)
You can write like this. In this code, f represents the first position of your array.
<ng-container *ngFor="let form of parentTabList; let i = index; let f = first">
<li *ngIf="f">
<a (click)="methodName(f)">
`{{f.label}}`
</a>
</li>
</ng-container>
If you want other position of your array, you can write like you mentioned above.
You can define a getter that will get you the index. This can then be used in the html
get firstIndex() {
return this.parentTabList.indexOf(this.parentTabList.find(({role}) =>
role.includes(this.userRole)))
}
Now in your html
<ng-container *ngFor="let form of parentTabList let i = index">
<li *ngIf="form.role.includes(userRole)">
<a [ngClass]="{redText: firstIndex === i}" (click)="methodName(form)">
{{form.label}}
</a>
</li>
</ng-container>
See Stackblitz Demo Here
I am making angular application with angular form.
Here i have given a form with input fields first name and last name which will always showing..
After that i am having children which will be displayed upon clicking the add button and the children will get removed on click remove button.
As of now everything works fine.
Here i am making patching of data to the inputs on click option from select box.. The neccessary inputs gets patched..
HTML:
<div>
<form (ngSubmit)="onSubmit()" [formGroup]="form">
<div *ngFor="let question of questions" class="form-row">
<ng-container *ngIf="question.children">
<div [formArrayName]="question.key">
<div *ngFor="let item of form.get(question.key).controls; let i=index" [formGroupName]="i">
<div *ngFor="let item of question.children">
<app-question [question]="item" [form]="form.get(question.key).at(i)"></app-question>
</div>
</div>
<select multiple (change)="changeEvent($event)">
<option *ngFor="let opt of persons" [value]="opt.key">{{opt.value}}</option>
</select>
</div>
</ng-container>
<ng-container *ngIf="!question.children">
<app-question [question]="question" [form]="form"></app-question>
</ng-container>
</div>
<div class="form-row">
<!-- <button type="submit" [disabled]="!form.valid">Save</button> -->
</div>
</form> <br>
<!-- Need to have add and remove button.. <br><br> -->
<button (click)="addControls('myArray')"> Add </button>
<button (click)="removeControls('myArray')"> Remove </button><br/><br/>
<pre>
{{form?.value|json}}
</pre>
</div>
TS:
changeEvent(e) {
if (e.target.value == 1) {
let personOneChild = [
{ property_name : "Property one" },
{ property_name : "Property two" },
]
for (let i = 0; i < personOneChild.length; i++) {
this.addControls('myArray')
}
this.form.patchValue({
'myArray': personOneChild
});
}
if (e.target.value == 2) {
let personTwoChild = [
{ property_name : "Property three" },
{ property_name : "Property four" },
{ property_name : "Property five" },
]
for (let i = 0; i < personTwoChild.length; i++) {
this.addControls('myArray')
}
this.form.patchValue({
'myArray': personTwoChild
});
}
}
addControls(control: string) {
let question: any = this.questions.find(q => q.key == control);
let children = question ? question.children : null;
if (children)
(this.form.get(control) as FormArray).push(this.qcs.toFormGroup(children))
}
removeControls(control: string) {
let array = this.form.get(control) as FormArray;
array.removeAt(array.length - 1);
}
Clear working stackblitz: https://stackblitz.com/edit/angular-x4a5b6-fnclvf
You can work around in the above link that if you select the person one option then the value named property one and property two gets binded to the inputs and in select box the property one is highlighted as selected..
The thing i am in need is actually from here,
I am having a remove button, you can see in demo.. If i click the remove button, one at last will be got removed and again click the last gets removed..
Here i am having two property one and two, if i remove both the inputs with remove button, the the highlighted value person one in select box needs to get not highlighted.
This is actually my requirement.. If i remove either one property then it should be still in highlighted state.. Whereas completely removing the both properties it should not be highlighted..
Hope you got my point of explanation.. If any needed i am ready to provide.
Note: I use ng-select for it as i am unable implement that library, i am making it with html 5 select box.. In ng-select library it will be like adding and removing the option.. Any solution with ng-select library also appreciable..
Kindly help me to achieve the result please..
Real time i am having in application like this:
Selected three templates and each has one property with one,two,three respectively:
If choose a dropdown then the property values for the respective will get added as children.
Here you can see i have deleted the property name three for which the parent is template three and the template three still shows in select box even though i removed its children
Firstly, get a reference to the select, like so:
HTML:
<select multiple (change)="changeEvent($event)" #mySelect>
<option *ngFor="let opt of persons" [value]="opt.key">{{opt.value}}</option>
</select>
TS:
import { ViewChild } from '#angular/core';
// ...
#ViewChild('mySelect') select;
Then, in your remove function, check if all elements have been removed, and if they have, set the value of the select to null
if (array.length === 0) {
this.select.nativeElement.value = null;
}
Here is a fork of the StackBlitz
I'm trying to create a table where the user can hide rows, and keep them hidden as they delete other rows.
In my html I use vuejs to bind a class when rendering the table:
<tr v-for="item in mylist" :class="{'noFruits': (item.fruits.length == 0)}">
There is a user checkbox to hide rows with that class:
<label><input type="checkbox" v-model="showBlankFruits" #change="setBlankDisplay">Show Blank Fruits</label>
In my Vue instance, the checkbox executes a method to hide/show rows with that class via jquery to attach the css display property:
methods: {
setBlankDisplay: function() {
if (this.showBlankFruits) {
$('.noFruits').css('display', '');
} else {
$('.noFruits').css('display', 'none');
}
},
In my jsfiddle, when a user deletes a row, the hidden row reappears. I see that attaching styles with jquery in this instance is not good... does anyone have a suggestion for a better method?
Mixing Vue and jQuery is not recommended, as you can do pretty much everything just using Vue and you don't get any conflicting operations that don't know what the other library/framework is doing.
The following will show the row if either the fruits array length is truthy, in other words not 0, or if showBlankFruits is true:
<tr v-for="item in mylist" v-show="item.fruits.length || showBlankFruits">
The following will toggle showBlankFruits when clicking the checkbox:
<label><input type="checkbox" v-model="showBlankFruits">Show Blank Fruits</label>
Full code example:
JSFiddle
You can also write something like this.
I've used computed and removed the jQuery part completely.
You must declare data as a function instead of an data object (https://v2.vuejs.org/v2/guide/components.html#data-Must-Be-a-Function)
You do not need to call the mounted method to set the initial state. It's already set with your data object.
In your code, you have to call mounted, because jQuery can only hide the results, when the DOM is loaded.
new Vue({
el: '#app',
data() {
return {
showBlankFruits: true,
mylist: [
{'user': 'Alice', 'fruits': [{'name': 'apple'}]},
{'user': 'Bob', 'fruits': [{'name': 'orange'}]},
{'user': 'Charlie', 'fruits': []},
{'user': 'Denise', 'fruits': [{'name': 'apple'}, {'name': 'orange'}]},
]
}
},
computed: {
list() {
return this.mylist.filter(item => (item.fruits.length > 0 && !this.showBlankFruits) || (item.fruits.length === 0 && this.showBlankFruits))
},
},
methods: {
delItem(item) {
let index = this.mylist.indexOf(item);
if (index > -1) {
this.mylist.splice(index, 1);
}
}
}
})
<script src="https://unpkg.com/vue"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<div id="app">
<label><input type="checkbox" v-model="showBlankFruits">Show Blank Fruits</label>
<br> <br>
<table>
<tr> <th class="col">User</th> <th class="col">Fruits</th> <th class="col"></th> </tr>
<tr v-for="item in list">
<td>{{ item.user }}</td>
<td> <span v-for="f in item.fruits"> {{ f.name }} </span> </td>
<td> <button #click="delItem(item)">Delete</button> </td>
</tr>
</table>
</div>
This is a great example of the power for declarative rendering rather than using DOM manipulation in components. The problem you are running into is when the Vue engine re-renders your list it doesn't know about the manual manipulation of elemets you did in the setBlankDisplay method. The way to get around that is to use component logic in the definition of the view itself, sort of like you did to set the noFruits class in the first place.
So, I propose you get rid of setBlankDisplay and replace it with the method:
itemDisplay(item) {
if (item.fruits.length === 0 && !this.showBlankFruits) {
return 'none';
}
return '';
},
Then you can reference it in the definition of your tr elements linked to a css display property, like so:
<tr v-for="item in mylist" :class="{'noFruits': (item.fruits.length == 0)}" :style="{display: itemDisplay(item)}">
I've updated the jsfiddle with this modification, showing that the state of hidden fruits remains when other items are deleted.
Take this as a general example of the dangers of using jquery to change the state of the view. Every effort should be taken to define the entire view in terms of component logic.
What is wrong with my Angular code? I am getting the following error:
Cannot read property 'remove' of undefined at BrowserDomAdapter.removeClass
<ol>
<li *ngClass="{active: step==='step1'}" (click)="step='step1'">Step1</li>
<li *ngClass="{active: step==='step2'}" (click)="step='step2'">Step2</li>
<li *ngClass="{active: step==='step3'}" (click)="step='step3'">Step3</li>
</ol>
Angular version 2+ provides several ways to add classes conditionally:
type one
[class.my_class] = "step === 'step1'"
type two
[ngClass]="{'my_class': step === 'step1'}"
and multiple option:
[ngClass]="{'my_class': step === 'step1', 'my_class2' : step === 'step2' }"
type three
[ngClass]="{1 : 'my_class1', 2 : 'my_class2', 3 : 'my_class4'}[step]"
type four
[ngClass]="step == 'step1' ? 'my_class1' : 'my_class2'"
You can find these examples on the documentation page
[ngClass]=... instead of *ngClass.
* is only for the shorthand syntax for structural directives where you can for example use
<div *ngFor="let item of items">{{item}}</div>
instead of the longer equivalent version
<template ngFor let-item [ngForOf]="items">
<div>{{item}}</div>
</template>
See also https://angular.io/docs/ts/latest/api/common/index/NgClass-directive.html
<some-element [ngClass]="'first second'">...</some-element>
<some-element [ngClass]="['first', 'second']">...</some-element>
<some-element [ngClass]="{'first': true, 'second': true, 'third': false}">...</some-element>
<some-element [ngClass]="stringExp|arrayExp|objExp">...</some-element>
<some-element [ngClass]="{'class1 class2 class3' : true}">...</some-element>
See also https://angular.io/docs/ts/latest/guide/template-syntax.html
<!-- toggle the "special" class on/off with a property -->
<div [class.special]="isSpecial">The class binding is special</div>
<!-- binding to `class.special` trumps the class attribute -->
<div class="special"
[class.special]="!isSpecial">This one is not so special</div>
<!-- reset/override all class names with a binding -->
<div class="bad curly special"
[class]="badCurly">Bad curly</div>
Another solution would be using [class.active].
Example :
<ol class="breadcrumb">
<li [class.active]="step=='step1'" (click)="step='step1'">Step1</li>
</ol>
That's the normal structure for ngClass is:
[ngClass]="{'classname' : condition}"
So in your case, just use it like this...
<ol class="breadcrumb">
<li [ngClass]="{'active': step==='step1'}" (click)="step='step1'">Step1</li>
<li [ngClass]="{'active': step==='step2'}" (click)="step='step2'">Step2</li>
<li [ngClass]="{'active': step==='step3'}" (click)="step='step3'">Step3</li>
</ol>
with the following examples you can use 'IF ELSE'
<p class="{{condition ? 'checkedClass' : 'uncheckedClass'}}">
<p [ngClass]="condition ? 'checkedClass' : 'uncheckedClass'">
<p [ngClass]="[condition ? 'checkedClass' : 'uncheckedClass']">
You can use ngClass to apply the class name both conditionally and not in Angular
For Example
[ngClass]="'someClass'">
Conditional
[ngClass]="{'someClass': property1.isValid}">
Multiple Condition
[ngClass]="{'someClass': property1.isValid && property2.isValid}">
Method expression
[ngClass]="getSomeClass()"
This method will inside of your component
getSomeClass(){
const isValid=this.property1 && this.property2;
return {someClass1:isValid , someClass2:isValid};
}
Angular provides multiple ways to add classes conditionally:
First way
active is your class name
[class.active]="step === 'step1'"
Second way
active is your class name
[ngClass]="{'active': step=='step1'}"
Third way
by using ternary operator class1 and class2 is your class name
[ngClass]="(step=='step1')?'class1':'class2'"
You should use something ([ngClass] instead of *ngClass) like that:
<ol class="breadcrumb">
<li [ngClass]="{active: step==='step1'}" (click)="step='step1; '">Step1</li>
(...)
In Angular 7.X
The CSS classes are updated as follows, depending on the type of the expression evaluation:
string - the CSS classes listed in the string (space delimited) are added
Array - the CSS classes declared as Array elements are added
Object - keys are CSS classes that get added when the expression given in the value evaluates to a truthy value, otherwise they are removed.
<some-element [ngClass]="'first second'">...</some-element>
<some-element [ngClass]="['first', 'second']">...</some-element>
<some-element [ngClass]="{'first': true, 'second': true, 'third': false}">...</some-element>
<some-element [ngClass]="stringExp|arrayExp|objExp">...</some-element>
<some-element [ngClass]="{'class1 class2 class3' : true}">...</some-element>
Additionally, you can add with method function:
In HTML
<div [ngClass]="setClasses()">...</div>
In component.ts
// Set Dynamic Classes
setClasses() {
let classes = {
constantClass: true,
'conditional-class': this.item.id === 1
}
return classes;
}
to extend MostafaMashayekhi his answer for option two>
you can also chain multiple options with a ','
[ngClass]="{'my-class': step=='step1', 'my-class2':step=='step2' }"
Also *ngIf can be used in some of these situations usually combined with a *ngFor
class="mats p" *ngIf="mat=='painted'"
You can use [ngClass] or [class.classname], both will work the same.
[class.my-class]="step==='step1'"
OR
[ngClass]="{'my-class': step=='step1'}"
Both will work the same!
While I was creating a reactive form, I had to assign 2 types of class on the button. This is how I did it:
<button type="submit" class="btn" [ngClass]="(formGroup.valid)?'btn-info':''"
[disabled]="!formGroup.valid">Sign in</button>
When the form is valid, button has btn and btn-class (from bootstrap), otherwise just btn class.
We can make class dynamic by using following syntax. In Angular 2 plus, you can do this in various ways:
[ngClass]="{'active': arrayData.length && arrayData[0]?.booleanProperty}"
[ngClass]="{'active': step}"
[ngClass]="step== 'step1'?'active':''"
[ngClass]="step? 'active' : ''"
Let, YourCondition is your condition or a boolean property, then do like this
[class.yourClass]="YourCondition"
The directive operates in three different ways, depending on which of three types the expression evaluates to:
If the expression evaluates to a string, the string should be one or more space-delimited class names.
If the expression evaluates to an object, then for each key-value pair of the object with a truthy value the corresponding key is used as a class name.
If the expression evaluates to an array, each element of the array should either be a string as in type 1 or an object as in type 2. This means that you can mix strings and objects together in an array to give you more control over what CSS classes appear. See the code below for an example of this.
[class.class_one] = "step === 'step1'"
[ngClass]="{'class_one': step === 'step1'}"
For multiple options:
[ngClass]="{'class_one': step === 'step1', 'class_two' : step === 'step2' }"
[ngClass]="{1 : 'class_one', 2 : 'class_two', 3 : 'class_three'}[step]"
[ngClass]="step == 'step1' ? 'class_one' : 'class_two'"
ngClass syntax:
[ngClass]="{'classname' : conditionFlag}"
You can use like this:
<ol class="breadcrumb">
<li [ngClass]="{'active': step==='step1'}" (click)="step='step1'">Step1</li>
<li [ngClass]="{'active': step==='step2'}" (click)="step='step2'">Step2</li>
<li [ngClass]="{'active': step==='step3'}" (click)="step='step3'">Step3</li>
</ol>
This is what worked for me:
[ngClass]="{'active': dashboardComponent.selected_menu == 'profile'}"
For elseif statement (less comparison) use like that: (For example you compare three statement)
<div [ngClass]="step === 'step1' ? 'class1' : (step === 'step2' ? 'class2' : 'class3')"> {{step}} </div>
Not relevant with [ngClass] directive but I was also getting the same error as
Cannot read property 'remove' of undefined at...
and I thought to be the error in my [ngClass] condition but it turned out the property I was trying to access in the condition of [ngClass] was not initialized.
Like I had this in my typescript file
element: {type: string};
and In my [ngClass] I was using
[ngClass]="{'active', element.type === 'active'}"
and I was getting the error
Cannot read property 'type' of undefined at...
and the solution was to fix my property to
element: {type: string} = {type: 'active'};
Hope it helps somebody who is trying to match a condition of a property in [ngClass]
<div class="collapse in " [ngClass]="(active_tab=='assignservice' || active_tab=='manage')?'show':''" id="collapseExampleOrganization" aria-expanded="true" style="">
<ul> <li class="nav-item" [ngClass]="{'active': active_tab=='manage'}">
<a routerLink="/main/organization/manage" (click)="activemenu('manage')"> <i class="la la-building-o"></i>
<p>Manage</p></a></li>
<li class="nav-item" [ngClass]="{'active': active_tab=='assignservice'}"><a routerLink="/main/organization/assignservice" (click)="activemenu('assignservice')"><i class="la la-user"></i><p>Add organization</p></a></li>
</ul></div>
Code is good example of ngClass if else condition.
[ngClass]="(active_tab=='assignservice' || active_tab=='manage')?'show':''"
[ngClass]="{'active': active_tab=='assignservice'}"
Try Like this..
Define your class with ''
<ol class="breadcrumb">
<li *ngClass="{'active': step==='step1'}" (click)="step='step1; '">Step1</li>
<li *ngClass="{'active': step==='step2'}" (click)="step='step2'">Step2</li>
<li *ngClass="{'active': step==='step3'}" (click)="step='step3'">Step3</li>
</ol>
The example is a bit big, but triggering a class instead of typing inline is my first preferred approach.
this way you can add as many possibilities as you want to your element.
There may be a way for those who want to bind more than one [ngClass] to a single element.
<span class="inline-flex items-center font-medium" [ngClass]="addClass">{{ badge.text }}</span>
import { ChangeDetectionStrategy, Component, Input } from '#angular/core';
type Badge = {
size?: 'basic' | 'large';
shape?: 'basic' | 'rounded';
color?: 'gray' | 'red' | 'yellow' | 'green' | 'blue' | 'indigo' | 'purple' | 'pink';
dot?: boolean;
removeButton?: false;
text?: string;
}
#Component({
selector: 'bio-badge',
templateUrl: './badge.component.html',
styleUrls: ['./badge.component.scss'],
changeDetection: ChangeDetectionStrategy.OnPush,
})
export class BioBadgeComponent {
#Input() badge!: Badge;
get addClass() {
return {
'px-2.5 py-0.5 text-sx': this.badge.size === 'basic',
'px-3 py-0.5 text-sm': this.badge.size === 'large',
'rounded-full': this.badge.shape === 'basic',
'rounded': this.badge.shape === 'rounded',
'bg-gray-100 text-gray-800': this.badge.color === 'gray',
'bg-red-100 text-red-800': this.badge.color === 'red',
'bg-yellow-100 text-yellow-800': this.badge.color === 'yellow',
'bg-green-100 text-green-800': this.badge.color === 'green',
'bg-blue-100 text-blue-800': this.badge.color === 'blue',
'bg-indigo-100 text-indigo-800': this.badge.color === 'indigo',
'bg-purple-100 text-purple-800': this.badge.color === 'purple',
'bg-pink-100 text-pink-800': this.badge.color === 'pink',
}
}
}
If user want to display the class on basis of && and ||
then below one is work for me
[ngClass]="{'clasname_1': condition_1 && condition_2, 'classname_2': condition_1 && condition2, 'classname_3': condition}"
Example:
[ngClass]="{'approval-panel-mat-drawer-side-left': similar_toil_mode==='side' && showsTheSimilarToilsWithCloseIcon, 'approval-panel-mat-drawer-side-right': similar_toil_mode==='side' && !showsTheSimilarToilsWithCloseIcon, 'approval-panel-mat-drawer-over': similar_toil_mode==='over'}"
I've run into an issue when creating multiple input[checkbox]es for a list of items in angular with ng-repeat and attaching an ng-model:
<li ng-repeat="item in items">
<a ng-href="#/{{item.id}}" > {{ item.id }} </a>
<input type="checkbox" ng-model="selectedMessages[item.id]"/>
</li>
The issue here is that selectedMessages[item.id] is only initialized and set when the checkbox is clicked once.
The reason this is necessary is that I would like to toggle all checkboxes with a single comand like so:
$scope.toggleCheckboxes = (state) ->
for key, val of $scope.selectedMessages
$scope.selectedMessages[key] = state # true or false
Let's say I have 3 checkboxes, and click 1 once, 2 twice, and 3 never, then said object will look like this:
$scope.selectedMessages = {
"1" : true,
"2" : false
}
So obviously, $scope.toggleCheckboxes(true) will only work for those checkboxes.
Is there a good way to initialize this ng-model for multiple checkboxes?
You can use ng-init to populate the array. I used $index rather than making up a bunch of data with id properties...adjust your code accordingly
<input type="checkbox"
ng-model="selectedMessages[$index]"
ng-init="selectedMessages[$index]=selectedMessages[$index]||false" />
JS
$scope.selectedMessages=[];
$scope.checkAll=function(){
var msgs = $scope.selectedMessages
msgs.forEach(function(elem, idx){
msgs[idx] =true
})
}
DEMO