core.js:4352 ERROR Error: If ngModel is used within a form tag, either the name attribute must be set or the form control must be defined as 'standalone' in ngModelOptions. code example

Example 1: If ngModel is used within a form tag, either the name attribute must be set or the form control must be defined as 'standalone' in ngModelOptions.

Example 2: <input [(ngModel)]="person.myfirstName" [ngModelOptions]="{standalone: true}">

Example 2: Error: If ngModel is used within a form tag, either the name attribute must be set or the form control must be defined as 'standalone' in ngModelOptions.

// If form is used, all the input fields which have [(ngModel)]="" must have 
// an attribute name with a value.

<input [(ngModel)]="firstname" name="something">