The issue with Angular's two-way data binding in a string array is that it is not functioning properly

Question

The issue with Angular's two-way data binding in a string array is that it is not functioning properly

Can someone help me understand the correct way to use ng-model in an array of strings?

I attempted the following:

Component.ts

toDos: string[] =["Todo1","Todo2","Todo3"];

Component.html

<div *ngFor="let item of toDos;let index = index">
   <input [(ngModel)]="toDos[index]" placeholder="item" name="word{{index}}">
</div>

Although this code does not show any errors, it doesn't update the input contents correctly. Can anyone provide guidance on the correct approach?

You can see the issue in action on this StackBlitz example when attempting to edit an input field: StackBlitz

I would appreciate any help or suggestions on how to resolve this problem. Thank you!

angular typescript

Answer 1

Answer №1

To keep track of the length of the to-dos list, you can create an auxiliary array called 'count' with the same length as the to-dos list.

toDos: string[] =["Todo1","Todo2","Todo3"];
count:number[]=new Array(this.toDos.length); //An auxiliary array
click(){
   this.toDos.push("Todo4");
   //if the length of the to-dos array changes, we need to update the count array as well
   this.count=new Array(this.toDos.length)
}

<!--we loop through the count array-->
<div *ngFor="let item of count;let index = index">
   <input [(ngModel)]="toDos[index]" placeholder="item" name="word{{index}}">
</div>

Answer 2

To keep track of the length of the to-dos list, you can create an auxiliary array called 'count' with the same length as the to-dos list.

toDos: string[] =["Todo1","Todo2","Todo3"];
count:number[]=new Array(this.toDos.length); //An auxiliary array
click(){
   this.toDos.push("Todo4");
   //if the length of the to-dos array changes, we need to update the count array as well
   this.count=new Array(this.toDos.length)
}

<!--we loop through the count array-->
<div *ngFor="let item of count;let index = index">
   <input [(ngModel)]="toDos[index]" placeholder="item" name="word{{index}}">
</div>

Answer 3

Answer №2

It appears that your code is correct. Hopefully, reviewing this will help you identify the root cause of the issue.

Take a look at this link for more details.

Answer 4

It appears that your code is correct. Hopefully, reviewing this will help you identify the root cause of the issue.

Take a look at this link for more details.

Answer 5

Answer №3

To access the value in the for loop, you can utilize the item directly within the loop

Answer 6

To access the value in the for loop, you can utilize the item directly within the loop

The issue with Angular's two-way data binding in a string array is that it is not functioning properly

Answer №1

Answer №2

Answer №3

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