interview questions

reactive forms angular example






single or first

First() will throw if it cannot find the first matching value, Single() will throw if it cannot find the value and if there are more than one matching element in the input sequence.



MVC Questions

Types of action filters:

  • output cache
  • Handle error
  • Authorize





Employee ob=new Employee();





[bind] classname obname






When you an HTML helper, such as LabelFor() or TextBoxFor(), it displays a model property in a fixed manner. For example, LabelFor() renders a model property name in a <label> tag and TextBoxFor() renders a textbox in which a model property is shown for editing. Although this arrangement works fine in many cases, at times you need more control over the way data is shown to the end user. Consider, for example, that you have a model property that represents currency. While displaying this property value to the end user, you want to show a currency symbol such as $ along with the property value. Such a customization is not possible with the above-mentioned HTML helpers. Another example could be a DateTime model property that needs to be displayed in a specific custom format.

  • DisplayFor()
  • DisplayForModel()
  • EditorFor()
  • EditorForModel()

Updatemodel with include and exclude properties






Editor template name is same as model name






Sharedàdisplay temaplatesàurl

[UiHint(“to give other displaytemplate name”)]



Automatically take the model and build the view…………

MvcBuildViews-àto enable compile time error checking



@html.raw-àwill take html tags and render it and display appropriately




-Java script:

  • Procedural oriented programming language
  • There is no class objects all code are writing in one place
  • Lot of code and conflicts
  • No compilation of code checking
  • Time taken process and no proper productivity and difficult to manage the huge applications


  • Will fallows oops features
  • Code can be clearly modularized
  • TS=JS+extra features[oops]+ES6[modren javascript]
  • installation of typescript
    1. Typescript compiler
    2. npm install typescript
  • compilation
    1. tsc test.ts[tsc   typescript compiler]
    2. this compiler will convert from typescript to javascript
  • excecution
    1. node test.js
  • check which version on typescript installed
    1. tsc -v





Typescript Basics


  1. let—block level scope in es6 they introduced
  2. var—function level scope and it will be accessed very closest function
  3. const—to const creations
  4. enum–group of constants

when var is there why let came?

to reduce the conflicts  we are using this let and name duplicacy…

and when u changed the value outside it becomes coflict


conditional statements: if, ifelse, ternery


  • foreach—visit and process the element and retrun nothing and performs some …… function there u can write logic on the item


  • map—visit and process the element and return the array


  • for…in—no separate function here 


  • include—>to check the particular value that is available in an array nt …will check with the help of include


  • reduce: it will always take previous result…..reduce.png
  • If u want to match the current value with previous value we need to use reduce…

    Accumulator-àis the result of last value

    Current valueàis the current idex

    1st timeàaccumulatorà20

    And current index is: 30


  • indexof : to check the index of where variable is availble, and return index and if the value is not available it will return -1 always



Angular installation

  • node js
  • npm
  • angular cli
  1. with the help of node will execute angular applications
  2. once your install the node you will get npm
  3. in one centralized place all packages so communicate that place we need npm
  4. node packages or modules
  5. angular cli —web pack tool…this is also a node module, its used to build the project,create and build and deploy the project, it will compile and produce the bundled file and that bundle we can exceute by browser
  6. ng—angular cli
    1. npm install -g @angular/cli—>  -g global means node_modules of c drive will store
    2. to know the version and to test its installed properly or not
    3. ng –version
  7. to create the app
    1. ng new projectname
  8. run the project
    1. ng server