Angular Fundamentals

Reactive vs. Template-Driven

The eternal battle: Simplicity vs. Control. Why I almost always choose Reactive Forms for scalable apps, but Template-Driven has its place.

Angular offers us two ways to build forms. Template-Driven is often the first encounter: It feels simple, almost magical. Minimal code, quick results.

But as requirements grow (complex validation, dynamic fields, unit tests), I often hit a wall with it. That’s why I rely on Reactive Forms in professional projects. Here’s why.

1. Template-Driven Forms (The "Easy" Way)

Almost everything happens in the HTML here. We use [(ngModel)] for two-way binding. This is great for a quick login form or prototypes, but the "single source of truth" lies in the template, not in the code. This makes testing difficult.

<!-- ⚠️ Logic is mixed into the template -->
<form #f="ngForm" (ngSubmit)="onSubmit(f)">

  <!-- We bind directly to a model object -->
  <input
    name="email"
    [(ngModel)]="model.email"
    required
    email>

  <!-- Validation check happens in HTML -->
  <div *ngIf="f.submitted && !f.valid">
    Error!
  </div>

  <button type="submit" [disabled]="f.invalid">
    Login
  </button>

</form>

💡

Pros & Cons: Extremely little boilerplate code in TypeScript. But: Unit tests are cumbersome since you need to render the template to test the logic.

2. Reactive Forms (The "Pro" Way)

With Reactive Forms, we explicitly define the structure in TypeScript. The HTML becomes just the "dumb" display. The model in the code is the truth. The data flow is synchronous and predictable.

import { Component, inject } from '@angular/core';
import { FormBuilder, Validators } from '@angular/forms';

export class LoginReactive {
  private fb = inject(FormBuilder);

  // ✅ Explicit & Typed Definition
  // The structure is defined here, not in HTML.
  loginForm = this.fb.group({
    email: ['', [Validators.required, Validators.email]],
    password: ['', [Validators.required, Validators.minLength(8)]]
  });

  submit() {
    if (this.loginForm.valid) {
      // We get a typed object: { email: string | null, ... }
      const rawValues = this.loginForm.getRawValue();
      console.log(rawValues);
    }
  }
}

<form [formGroup]="loginForm" (ngSubmit)="submit()">

  <!-- Clean binding via formControlName -->
  <!-- The HTML is "dumb" - it knows nothing about rules -->
  <input formControlName="email" type="email">

  <input formControlName="password" type="password">

  <button type="submit" [disabled]="loginForm.invalid">
    Login
  </button>

</form>

3. When to Use What?

Technically, both approaches have their merits. Here’s my decision-making guide:

Template-Driven

✅ Simple forms (Login, Newsletter)
✅ Prototyping / MVP
❌ Complex Validation dependencies
❌ Unit Testing logic is hard

Reactive Forms

✅ Scalable Enterprise Apps
✅ Dynamic Fields (FormArray)
✅ Complex Validation Rules
✅ Easy to Unit Test (No HTML needed)

The Golden Rule: Consistency

Regardless of pros and cons, I have one iron rule: I never mix both concepts in a single project.

I decide on one approach at the start (usually Reactive) and stick to it – even for the smallest checkbox. Nothing confuses a team more than seeing [(ngModel)] in file A and formControlName in file B.

💡

RxJS Power: A huge advantage of Reactive Forms is .valueChanges. You can observe changes as a stream (e.g., debounceTime(300) for a search), which is hard to achieve with Template-Driven.