how to define static constants in typescript and angular

Define an abstract class for your constants:

export abstract class Constants {  static readonly STUDENT_NAMES: string[] = ["JOHN", "BOB", "NICK"];  static readonly TEACHER_NAME: string[] = ["HARRY", "CHRIS"];  static readonly SCHOOL_CODE: number[] = [100, 102, 107];}

Then include this class whereever needed with import { Constants } from '...'; and use its values with const names: string[] = Constants.STUDENT_NAMES;

Regarding the naming I agree with @AdrianBrand to prefer names like studentNames, teacherNames and schoolCodes.

Edit: TypeScript 3.4 introduced so called const assertions, which might also be suited:

export const constants = {  studentNames: ["JOHN", "BOB", "NICK"],  ...} as const;

You put them in a TypeScript file and import them where needed.

export const STUDENT_NAMES: string[] = ["JOHN","BOB","NICK"];

Put it in student-names.ts

import { STUDENT_NAMES } from './path/cosnstants/student-names';

where you need it.

Personally I would name them studentNames and not STUDENT_NAMES but that is a matter of taste.

You can create a TS file constants.ts that contains all your constants :

export const constants = {   STUDENT_NAMES: ["JOHN","BOB","NICK"],   TEACHER_NAME: ["HARRY","CHRIS"],   SCHOOL_CODE: [100,102,107]};

Then whenever you need a constant you can call it like this code bellow:

let studentsNames : any = constants.STUDENT_NAMES;

Regards,