PART-3 INTERVIEW TYPE QUESTIONS ( [ngModel], [(ngModel)], FormsModule ..... )

 1. What is camel case and pascal case?

• With camelCase, the first letter of the first word in the identifier is lower case, while the first letter of every subsequent word is uppercase. for eg: newMaheshIdentifier.
• And with PascalCase, the first letter of every word in the identifier is upper case. For eg: NewMaheshIdentifier.

2. What are directives?

Directives are custom HTML attributes which tell angular to change the style or behavior of the DOM elements.

3. What is the use of ngModel and significance of [  ] and ( ) in ngModel?

ngModel is a directive which binds input, stores the required user value in a variable, and select the textarea and we can use that variable whenever we require that value; It also used during validation in a form. We can use ngModel with:

1. Input

• text 
• chechbox
• radio
• number
• email
• url
• date
• datetime-local
• time

2. select

3. textarea

• [ngModel] - it's property binding only, not two-way binding. So entering new value will not update overRideRate. And [ngModel] is just show up.

• [(ngModel)] is two-way binding that comes from Angular.

4. What are expressions or interpolation?

Interpolation refers to embedding expressions into marked up text. By default, interpolation uses as its delimiter the double curly braces, like: {{mahesh}} .

For eg:

<h1>Current customer: {{ maheshApplication }}</h1>

5. What is the importance of FormsModule?

FormsModule exports the required providers and directives for template-driven forms, making them available for import by NgModules that import this module. It contains the directives as: CheckboxControlValueAccessor, NumberValueAccessor, PatternValidator etc

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