Setting form values in Angular using NgForm.setValue() with the ability to include optional

Question

Setting form values in Angular using NgForm.setValue() with the ability to include optional

I am working with a Template driven form in Angular where I need to populate values upon clicking on a product. The 'description' and 'imageUrl' fields may sometimes be undefined, which can cause issues with my form if not handled properly. My current solution involves using a ternary operator:

  private initFormEdit() {
    this.product = this.productService.fetchProduct(this.restaurantId, this.productId);

    // Using a ternary operator to set default values for empty objects
    const description = this.product.description ? this.product.description : '';
    const imageUrl = this.product.imageUrl ? this.product.imageUrl : '';

    this.productForm.setValue({
      name: this.product.name,
      category: this.product.category,
      description,
      price: this.product.price,
      imageUrl
    });
  }

Are there any more efficient or cleaner alternatives to achieve the same result? Appreciate any suggestions!

typescript angular-template-form

Answer 1

Answer №1

In Angular, there are two methods called patchValue and setValue.

When using setValue, every field defined in the form must be supplied. However, with patchValue, this is not necessary.

For example:

// Using setValue
this.productForm.form.setValue({
      name: this.product.name,
      category: this.product.category,
      price: this.product.price,
    });

// Using patchValue
this.productForm.form.patchValue({
      name: this.product.name,
      category: this.product.category,
      price: this.product.price,
    });

It is important to note that the form itself contains a formGroup named form which must be used because ngForm does not have the patchValue method.

UPDATE
There are some considerations when using patchValue with template-driven forms, depending on when you call it.
You could also consider using a mapper or initializer to fill in any missing or undefined properties of your object.
Overall, I would recommend using the patchValue approach if possible.

Answer 2

In Angular, there are two methods called patchValue and setValue.

When using setValue, every field defined in the form must be supplied. However, with patchValue, this is not necessary.

For example:

// Using setValue
this.productForm.form.setValue({
      name: this.product.name,
      category: this.product.category,
      price: this.product.price,
    });

// Using patchValue
this.productForm.form.patchValue({
      name: this.product.name,
      category: this.product.category,
      price: this.product.price,
    });

It is important to note that the form itself contains a formGroup named form which must be used because ngForm does not have the patchValue method.

UPDATE
There are some considerations when using patchValue with template-driven forms, depending on when you call it.
You could also consider using a mapper or initializer to fill in any missing or undefined properties of your object.
Overall, I would recommend using the patchValue approach if possible.

Setting form values in Angular using NgForm.setValue() with the ability to include optional

Answer №1

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