Using Angular 2, I want to duplicate a line in a template multiple times. Iterating over an object is easy, *ngFor="let object of objects". However, I want to run a simple for loop, not a foreach loop. Something like (pseudo-code):
{for i = 0; i < 5; i++}
<li>Something</li>
{endfor}
How would I do this?
You could dynamically generate an array of however time you wanted to render <li>Something</li>, and then do ngFor over that collection. Also you could take use of index of current element too.
Markup
<ul>
<li *ngFor="let item of createRange(5); let currentElementIndex=index+1">
{{currentElementIndex}} Something
</li>
</ul>
Code
createRange(number){
// return new Array(number);
return new Array(number).fill(0)
.map((n, index) => index + 1);
}
Under the hood angular de-sugared this *ngFor syntax to ng-template version.
<ul>
<ng-template ngFor let-item [ngForOf]="createRange(5)" let-currentElementIndex="(index + 1)" [ngForTrackBy]="trackByFn">
{{currentElementIndex}} Something
</ng-template>
</ul>
count : int amount of times, my property's number is.
You can instantiate an empty array with a given number of entries if you pass an int to the Array constructor and then iterate over it via ngFor.
In your component code :
export class ForLoop {
fakeArray = new Array(12);
}
In your template :
<ul>
<li *ngFor="let a of fakeArray; let index = index">Something {{ index }}</li>
</ul>
The index properties give you the iteration number.
new Array(i); in a pipe so that it would be reusable <li *ngFor="let a of 12 | fakeArray; let index = index">Something {{ index }}</li>, pipe code: transform(i: number) { return new Array(i) };Depending on the length of the wanted loop, maybe even a more "template-driven" solution:
<ul>
<li *ngFor="let index of [0,1,2,3,4,5]">
{{ index }}
</li>
</ul>
You can do both in one if you use index
<div *ngFor="let item of items; let myIndex = index>
{{myIndex}}
</div>
With this you can get the best of both worlds.
4.2.4^ still. Just wanted to write this since some Angular 2+ is still in flux. I was looking to just get the iterations of an existing array printed in a table and this is the most succinct and elegant solution (IMO)
The better way to do this is creating a fake array in component:
In Component:
fakeArray = new Array(12);
InTemplate:
<ng-container *ngFor = "let n of fakeArray">
MyCONTENT
</ng-container>
queNumMin = 23;
queNumMax= 26;
result = 0;
for (let index = this.queNumMin; index <= this.queNumMax; index++) {
this.result = index
console.log( this.result);
}
Range min and max number
you can use _.range([optional] start, end). It creates a new Minified list containing an interval of numbers from start (inclusive) until the end (exclusive). Here I am using lodash.js ._range() method.
Example:
CODE
var dayOfMonth = _.range(1,32); // It creates a new list from 1 to 31.
//HTML Now, you can use it in For loop
<div *ngFor="let day of dayOfMonth">{{day}}</div>
import * as _ from 'lodash' or something similar.The best answer for this question I have found here
You need to create an attribute inside your class and reference it to Array object:
export class SomeComponent {
Arr = Array; //Array type captured in a variable
num:number = 20;
}
And inside your HTML you can use:
<ul id="next-pages">
<li class="line" *ngFor="let _ of Arr(10)"> </li>
</ul>
for Example let say you have an array called myArray if you want to iterate over it
<ul>
<li *ngFor="let array of myArray; let i = index">{{i}} {{array}}</li>
</ul>
You can do like this in a simple way,
<div *ngFor="let i of ('a,'.repeat(100).split(','))">
.....
</div>
('a,'.repeat(100).split(',')) --> it means construct a long concatenated string of a, 100 times and then split it by , results in array of 100 items, which ngFor picks up and iterate 100 times.
1.generate a pipe for example "ng g p range"
transform(length: number):any[]{
return new Array(length);
}
2.in html
<div *ngFor="let _ of (12|range)" > ... </div>
I would suggest a spread operator in a loop like this, if you're using Angular :
this.triggersList = res.content;
for (let index = 0; index < 10; index++) {
this.triggersList.push(...this.triggersList);
}
this.totalItems = res.totalElements;
*Believing the original question could be expanded to the correct use of the engine, populating the html's list all the same.
If you want to use the object of ith term and input it to another component in each iteration then:
<table class="table table-striped table-hover">
<tr>
<th> Blogs </th>
</tr>
<tr *ngFor="let blogEl of blogs">
<app-blog-item [blog]="blogEl"> </app-blog-item>
</tr>
</table>
If you want duplicate lines multiple time.
You can simply do :-
declare in .ts file
public repeater = "<li>Something</li>";
Then use following to print it .html file.
{{repeater.repeat(5)}}
