I have a html component with list
<div *ngFor="let item of myArr">
<ul>
<li>
{{ item }}
<span>
<mat-icon (click)="expression($event)">add</mat-icon>
</span>
<ng-container
><h2 *ngFor="let item of textArr">
{{ item }}
</h2></ng-container
>
</li>
</ul>
</div>
and component ts with arrays
import { Component, OnInit } from '#angular/core';
#Component({
selector: 'app-child',
templateUrl: './child.component.html',
styleUrls: ['./child.component.scss'],
})
export class ChildComponent implements OnInit {
myArr = ['1', '2', '3', '4'];
abc = ['a', 'b', 'c', 'd'];
textArr = [];
constructor() {}
ngOnInit(): void {}
expression(ev: Event) {
console.log(ev);
this.textArr.push(this.abc);
}
}
how can I make, that when I click + what is on front of 1, then 'a' form abc will be displayed only under 1, if I click + what is on front of 2, then b from abc should be display under 2, etc...
Use the index in for loop.
I have an example
<h2>Form list</h2>
<div *ngFor="let form of formList; let i = index">
<ul>
<li>
<h4>{{ form.formLable }}</h4>
<div>
<button (click)="loadForm(i)">View {{ form.formLable }}</button>
</div>
<div *ngIf="form.isLoaded">
Do what ever strategy to load a form in
If many many many forms look at loading components in dynamically
</div>
</li>
</ul>
</div>
Here is a working example.
https://stackblitz.com/edit/angular-8clu3r?file=src%2Fapp%2Fform-list%2Fform-list.component.html
I think you're asking how to put the corresponding value from one array below an item in the list, e.g. pressing add next to 1 would show a, 3 would show c.
I think your best bet is to pass the index of the loop into your function 'expression'. You can get the index of your loop by adding index as i to your loop, so it would look something like this.
<div *ngFor="let item of myArr; index as i">
<ul>
<li>
{{ item }}
<span>
<mat-icon (click)="expression($event, i)">add</mat-icon>
</span>
...
Now you need a structure to store the values that have been added, I would look at using a 2D array (an array of arrays) to store your added values and display them using your for loops and indexes.
Hope this helps 😊
Related
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
In angular 6 I want to access *ngFor last value as I want to operation if last value is set
eg
<li [ngClass]="list.mydata==1?'replies a':'sent a'" *ngFor="let list of chatlist; let last=last;">
<span [last]="last"></span>
<img src="{{list.profile_img}}" alt="" />
<div *ngIf="list.sender_type==0">
<p>{{list.message}}{{last}}</p>
</div>
<div *ngIf="list.sender_type==1">
<p style="background-color: burlywood;">{{list.message}}</p>
</div>
</li>
I want to do is [(myvar)]=last in place of let last=last
I want to bind the last variable so, I can access it is set or not in its component.
you can create a custom directive:
import { Directive, Output, EventEmitter, Input } from '#angular/core';
#Directive({
selector: '[onCreate]'
})
export class OnCreate {
#Output() onCreate: EventEmitter<any> = new EventEmitter<any>();
constructor() {}
ngOnInit() {
this.onCreate.emit('dummy');
}
}
and then you can use it in your *ngFor to call the method in your component:
<li [ngClass]="list.mydata==1?'replies a':'sent a'" *ngFor="let list of chatlist; let last=last;">
<span (onCreate)="onCreate(last)"></span>
<img src="{{list.profile_img}}" alt="" />
<div *ngIf="list.sender_type==0">
<p>{{list.message}}{{last}}</p>
</div>
<div *ngIf="list.sender_type==1">
<p style="background-color: burlywood;">{{list.message}}</p>
</div>
</li>
then in your component:
myvar: boolean = false;
onCreate(last) {
this.myvar = last;
}
checkout this DEMO.
Angular provides certain local variables when using *ngFor, one is for example last, which will (not as you expect currently) be a boolean value, being true if it is the last item. This is meant for adding specific stylings for the example to the last element of a list.
If you want that boolean you already use it correctly, but obviously the element using it should be a component. So instead of
<span [last]="last"></span>
it should be something like
<my-component [last]="last"></my-component>
where in my-component you define
#Input last: boolean;
and thus have access to it.
for example
<li [ngClass]="list.mydata==1?'replies a':'sent a'" *ngFor="let list of chatlist; let index=i;">
</li>
now you excess last elemnt like
<anyTag *ngIf="i === chatlist.length-1"></anyTag>
In the above screenshot console I have an object with 2 values users and tickers. Again each one is array of values.
Now how to display these values in angular5 html template as specified in above screenshot?
I am trying to use ngFor but it is showing errors.
Suppose this is your data:
public data = {
tickers:[
{id:"1",name:"Ticker Name 1", company:"Company 1"},
{id:"2",name:"Ticker Name 2", company:"comapny 2"}
],
users:[
{id:"1",first_name:"User1 ", last_name:"u1last", email:"user1#test.com"},
{id:"2",first_name:"User2", last_name:"u2last", email:"user2#test.com"},
{id:"3",first_name:"User3", last_name:"u3last", email:"user3#test.com"},
{id:"4",first_name:"User4", last_name:"u4last", email:"user4#test.com"}
]
};
public dataKeys; // This will hold the main Object Keys.
The constructor will look something like this:
constructor() {
this.dataKeys = Object.keys(this.data);
}
Here is the simple HTML that you need to write:
<div *ngFor="let key of dataKeys">
<h3>{{ key }}</h3>
<ul>
<li *ngFor="let d of data[key]">{{d.name || d.first_name}}</li>
</ul>
</div>
Here is the complete working plunker for your case:
Click here to view the Working Solution
you can use like that,
<ul>
<P>users</p>
<li *ngFor="let item of object.users; let i = index">
{{i}}. {{item.frist_name}}
</li>
<P>Tickets</p>
<li *ngFor="let item of object.tickers; let i = index">
{{i}}. {{item.name}}
</li>
</ul>
According to the documentation it should be this:
Users:
<ol>
<li *ngFor="let user of users">{{user.first_name}}</li>
</ol>
Tickets:
<ol>
<li *ngFor="let ticket of tickets">{{ticket.name}}</li>
</ol>
You can use json pipe for debug purpose like this:
{{object |json}}
If you want exactly as in picture, look at this solution. With this case, you don't need to manually write first level property names of object in template for using *ngFor
I'm running into a problem with creating a dynamic class name based on the Angular 2 ngFor loop index. I had to use the following syntax because Angular 2 does not like ngFor and ngIf on the same element.
With this syntax, how can I create a dynamic class name with the value of index at {{index}}. I know this isn't proper A2 code, but I put it in my code example to show you where I would like the value to appear.
<div class="product-detail__variants">
<template ngFor #variant [ngForOf]="variants" #index="index">
<div *ngIf="currentVariant == index">
<div class="product-detail-carousel-{{index}}">
</div>
</div>
</template>
</div>
The value "variants" is an empty array of a set length. "variant" thus has no value.
"currentVariant" is a number that by default equals 0.
EDIT: This code above is correct. I had another extraneous error that I thought was connected to this code.
I don't really understand your problem ;-)
There are two ways to set classes for a specific element:
The way you do with curly brackets:
#Component({
selector: 'my-app',
template: `
<div class="product-detail__variants">
<template ngFor #variant [ngForOf]="variants" #index="index">
<div *ngIf="currentVariant == index">
<div class="product-detail-carousel-{{index}}">
Test
</div>
</div>
</template>
</div>
`,
styles: [
'.product-detail-carousel-2 { color: red }'
]
})
Test is displayed only for the third element (index 2) and in red.
As suggested by #Langley using the ngClass directive
import {NgClass} from 'angular2/common';
#Component({
selector: 'my-app',
template: `
<div class="product-detail__variants">
<template ngFor #variant [ngForOf]="variants" #index="index">
<div *ngIf="currentVariant == index">
<div class="product-detail-carousel-{{index}}">
Test
</div>
</div>
</template>
</div>
`,
styles: [
'.product-detail-carousel-2 { color: red }'
],
directives: [ NgClass ]
})
The different is that you need to specify the NgClass directive within the providers attribute of your component. Again Test is displayed only for the third element (index 2) and in red.
Your following sentences: "The value variants is an empty array of a set length. variant thus has no value. currentVariant is a number that by default equals 0.". How do you expect something to be displayed if your array is empty. An ngFor is an iteration...
Hope it helps you,
Thierry
In case anyone is looking to add a specific class based on the index, you can do something like this. I personally prefer the syntax here too. Let's say you wanted to add last-para to the last paragraph from an array:
<p
*ngFor="let p of paragraphs; let i = index"
[class.last-para]="i >= paragraphs.length - 1">
{{p}}</p>
Is it not possible (or not yet possible) to use ngModel against values from ngFor? Is Angular trying to protect me from bad performance?
Works great: http://jsfiddle.net/langdonx/n5pjgev6/
<input type="text" [(ng-model)]="value">{{value}}
Does not work so great: http://jsfiddle.net/langdonx/n5pjgev6/1
<li *ng-for="#name of names">
<input type="text" [(ng-model)]="name">{{name}}
</li>
EXCEPTION: Cannot reassign a variable binding name
I tried binding to the array as well, which... kind of works, but hijacks focus and also throws an exception: http://jsfiddle.net/langdonx/n5pjgev6/2/
<li *ng-for="#name of names; #i = index">
<input type="text" [(ng-model)]="names[i]">{{name}}
</li>
EXCEPTION: LifeCycle.tick is called recursively
Edit:
I can get around the LifeCycle.tick issue using a more direct approach, but the focus is still stolen because ngFor redraws things: http://jsfiddle.net/langdonx/n5pjgev6/3/
<li *ng-for="#name of names; #i = index">
<input type="text" [value]="names[i]" (input)="names[i] = $event.target.value">{{names[i]}}
</li>
I think ngFor don't like tracking array elements which are primitive values having ngModel on them.
If you remove the ngModel inside the loop, it works.
It works too when I update jsfiddle with :
this.names = [{name: 'John'}, {name: 'Joe'}, {name: 'Jeff'}, {name: 'Jorge'}];
and
<li *ng-for="#n of names"><input type="text" [(ng-model)]="n.name">{{n.name}}</li>
A solution is to reference the value inside ngModel by its index. Therefore [(ngModel)]="names[index]".
But this is not sufficient because *ngFor tracks items by value. As soon as the value is changed the old value cannot be tracked. So we need to change the tracking function to return an index, thus trackBy: trackByIndex.
This issue is explained here.
Solution:
#Component({
selector: 'my-app',
template: `
<div>
<input type="text"
*ngFor="let name of names; let nameIndex = index; trackBy: trackByIndex"
[(ngModel)]="names[nameIndex]"/>
<br/>
{{ names | json }}
</div>
`,
})
export class App {
names: string[];
constructor() {
this.names = ['a', 'b', 'c'];
}
public trackByIndex(index: number, item) {
return index;
}
}