does ngModel create two way data binding if used without “banana” wrapping

问题

In this article Todd Motto explains that:

ngModel = if no binding or value is assigned, ngModel will look for a name attribute and assign that value as a new Object key to the global ngForm Object:

<form novalidate #f="ngForm">
  ...
    <input
     type="text"
     placeholder="Your full name"
     ngModel>
  ...
</form>

And about "banana" wrapping:

[(ngModel)] = two-way binding syntax, can set initial data from the bound component class, but also update it:

<form #f="ngForm">
  ...
    <input
      type="text"
      placeholder="Your full name"
      name="name"
      [(ngModel)]="user.name">
  ...
</form>

So I was expecting to see [(ngModel)] used in his final example. However, he used the plain ngModel directive. Does it create two-way data-binding? It seems that it doesn't create any binding at all.

回答1:

It creates one way binding to form.value[name], ngModel in this case just updates corresponding property in forms value object.

See https://angular.io/docs/ts/latest/api/forms/index/NgModel-directive.html

来源：https://stackoverflow.com/questions/42191427/does-ngmodel-create-two-way-data-binding-if-used-without-banana-wrapping