Disable button when input is empty in Angular 2

Question

I want to check whether the input is empty.

• If not empty, enable the submit button.
• If empty, disable the submit button.

I tried (oninput) and (onchange), but they do not run.

<input type="password" [(ngModel)]="myPassword" (oninput)="checkPasswordEmpty()"/>

checkPasswordEmpty() {
    console.log("checkPasswordEmpty runs");
    if (this.myPassword) {
        // enable the button
    }
}

Answer 1

In this case, I would leverage form validators. I would add the "required" validation on your input and use the global state of your form to disable / enable your button.

With the template-driven approach, there is no code to add in your component, only stuff in its template...

Here is sample below:

<form #formCtrl="ngForm">
  <input ngControl="passwordCtrl" required>
  <button [disabled]="!formCtrl.form.valid">Some button</button>
</form>