Tips for utilizing enum types in Typescript

Question

Tips for utilizing enum types in Typescript

My goal is to design a Question class that requires various types of responses for different scenarios. These responses can be in the form of a DoAnswer (e.g. "run") or a CheckAnswer (e.g. "check the clock"). I have created separate enums for these response types since there are only a limited number of possible actions and checks in my specific case, each needing a unique name and display string, making enums the ideal choice. Now, I am looking for a way to store the expected answer type for each question.

I had considered using something like answerType: enum;, but this approach does not work as an enum cannot be used as a value type. In Java, you could use Class<?> answerType, but I am unsure how to achieve similar functionality in TypeScript.

The reason behind needing this information is that I want to determine the correct answer based on the expected type for a given question, like so:

this.correctAnswers: DoAnswer[] | CheckAnswer[];

if(answerType is DoAnswer) {
  this.correctAnswers = answerService.calculateCorrectDoAnswers();
  // Here, answerService retrieves possibleAnswers and situationInQuestion
}

It's possible that I may be misunderstanding some key concepts, but at the moment, I am unable to see a more effective solution.

angular typescript enums typing

Answer 1

Answer №1

Enumerate

export enum QuestionList {
  ToAnswer = 'execute',
  VerifyAnswer = 'inspect the time'
};

Data Type

export type AnswerType = QuestionList.ToAnswer | QuestionList.VerifyAnswer;

Module

checkResponse(answer: AnswerType): void {
    if (answer === 'execute') {
      console.log('run')
    }

    if (answer === 'inspect the time') {
      console.log('clock')
    }

    // The statement below won't compile as the value is not defined
    if (answer === 'something else') 
  }

UPDATE:

There may be other methods, but you could try it this way:

Data Types

export type ActionsToDo =
  | 'execute'
  | 'alert the authorities'
  | 'dial emergency services'
  | 'cry for help';

export type ChecksToPerform =
  | 'inspect clock'
  | 'examine weapon'
  | 'survey location'
  | 'verify vehicles';

Response Utility

export const actionResponses = ['execute', 'alert the authorities', 'dial emergency services', 'cry for help'];
export const checkResponses = [
  'inspect clock',
  'examine weapon',
  'survey location',
  'verify vehicles',
];

Interactive Module

analyze(val: ActionsToDo | ChecksToPerform) {
    if (actionResponses.includes(val)) {
      // Action needed
    }

    if (checkResponses.includes(val)) {
      // Verification required
    }
  }

Answer 2

Enumerate

export enum QuestionList {
  ToAnswer = 'execute',
  VerifyAnswer = 'inspect the time'
};

Data Type

export type AnswerType = QuestionList.ToAnswer | QuestionList.VerifyAnswer;

Module

checkResponse(answer: AnswerType): void {
    if (answer === 'execute') {
      console.log('run')
    }

    if (answer === 'inspect the time') {
      console.log('clock')
    }

    // The statement below won't compile as the value is not defined
    if (answer === 'something else') 
  }

UPDATE:

There may be other methods, but you could try it this way:

Data Types

export type ActionsToDo =
  | 'execute'
  | 'alert the authorities'
  | 'dial emergency services'
  | 'cry for help';

export type ChecksToPerform =
  | 'inspect clock'
  | 'examine weapon'
  | 'survey location'
  | 'verify vehicles';

Response Utility

export const actionResponses = ['execute', 'alert the authorities', 'dial emergency services', 'cry for help'];
export const checkResponses = [
  'inspect clock',
  'examine weapon',
  'survey location',
  'verify vehicles',
];

Interactive Module

analyze(val: ActionsToDo | ChecksToPerform) {
    if (actionResponses.includes(val)) {
      // Action needed
    }

    if (checkResponses.includes(val)) {
      // Verification required
    }
  }

Tips for utilizing enum types in Typescript

Answer №1

Similar questions

Encountering issues while incorporating decimal.js in TypeScript

Combining the output of two Observables through the CombineLatest method to generate a

The styling of Primeng Carousel appears to be incorrect

My browser is able to display the JSON response from an HTTP request, as well as the REST client, but

Having trouble applying CSS styling to the div element

The value currently displayed in the Angular 6 Material mat-selection-list

Is there a way to position the label to the left side of the gauge?

Use ng2-select2 directive to connect a reactive form formControlName

Tips for utilizing a bootstrap navbar and dropdown in conjunction with angular 7

Tips for accessing the app instance within a module in Nest.js

What is the best way to have an icon appear when a child component div is clicked, without it displaying on other similar divs?

Tips for successfully sending an interface to a generic function

incongruity discovered during string conversion in HmacSHA256 within Ionic framework

Executing a service call test within my component's unit test

Utilizing regular expressions to search through a .md file in JavaScript/TS and returning null

What could be causing the 404 error that occurs when attempting to post from an Angular2 application to PHP?

React - All subsequent variable declarations must be of the same type

Utilizing Typescript Decorators to dynamically assign instance fields within a class for internal use

Error 16 occurred when attempting to ngUpgrade two different versions of Highcharts

Organizing Firebase functions: Managing multiple functions and dependencies