How to handle Null check for trim () & toLowerCase() in Angular 7

Question

I have an input field in Angular 7 for that i use trim () and toLowerCase() the logic works but some times in console it shows .trim() and toLowerCase() of undefined how to handle this errors please help.

             <input
             oninput="this.value = this.value.toLowerCase()"
             (blur)="supplierInfo.name = supplierInfo.name.trim()"
             [(ngModel)]="supplierInfo.name" 
              />

Nayak · Accepted Answer · 2020-05-21 07:19:15Z

1

You can do null/undefined checks by using safe navigation operator ( ? )

For example:

(blur)="supplierInfo?.name = supplierInfo?.name?.trim()"

Adding the same for this.value

oninput="this.value = this.value?.toLowerCase()" - In this case, it the new value is null/undefined - then it will retain the same
oninput="this.value = this.value?.toLowerCase() || ''" - Will update the string to a blank string

edited May 21, 2020 at 7:19

answered May 21, 2020 at 6:07

Nayak

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3 Comments

Sai Ram Over a year ago

how to do for this one oninput="this.value = this.value.toLowerCase()"

Nayak Over a year ago

Depends what you want. You can use this.value = this.value?.toLowerCase(). This will set the value to undefined. And you can also set it to blank using this.value = this.value?.toLowerCase() || ''

Sai Ram Over a year ago

Ho to provide null check for this one {{ itemFornew.location.addressLine2 }}

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