Assign a true or false value to every attribute of an object

Question

Assign a true or false value to every attribute of an object

Imagine we have a scenario with an interface like this:

    interface User {
       Id: number;
       FirstName: string;
       Lastname: string;
       Age: number;
       Type: string;
    }

and a specific method for copying properties based on a flag.

    function copyIfAccepted<T extends object, K extends keyof T>(source: T, dest: T, key: K, 
  isAccepted: boolean) {
      if (isAccepted && source[key] !== dest[key]) {
        dest[key] = source[key];
      }
    }

Currently, the method is being called multiple times for each property. Keep in mind that not all properties are listed here.

     copyIfAccepted(oldUser, newUser, 'Id', true);
     copyIfAccepted(oldUser, newUser, 'FirstName', false);
     copyIfAccepted(oldUser, newUser, 'LastName', true);
     copyIfAccepted(oldUser, newUser, 'Age', true);

Is there a way to refactor this method so it only needs to be called once for all relevant properties? This should be done using TS 4.9

typescript

Answer 1

Answer №1

As previously stated in my comment, a helper type can be created to iterate over any type and convert it into an object with its attributes as booleans for the "isActive" part:

interface User {
  Id: number;
  FirstName: string;
  Lastname: string;
  Age: number;
}

type ToBooleanType<T> = {
  [P in keyof T]: boolean;
};

function copyIfAccepted<T extends object>(source: T, dest: T, checks: ToBooleanType<T>) {
  for (const key in source) {
    const sourceValue = source[key];
    const destValue = dest[key];
    const isAccepted = checks[key];

    if (isAccepted && sourceValue !== destValue) {
      dest[key] = sourceValue;
    }
  }
}
const user1: User = { Age: 21, FirstName: 'Joe', Id: 1, Lastname: 'Dirt' };
const user2: User = { Age: 26, FirstName: 'Jane', Id: 3, Lastname: 'Doe' };

copyIfAccepted(user1, user2, { Id: false, Age: true, FirstName: false, Lastname: true });

console.log(user1, user2);

Output:

[LOG]: {
  "Age": 21,
  "FirstName": "Joe",
  "Id": 1,
  "Lastname": "Dirt"
},  {
  "Age": 21,
  "FirstName": "Jane",
  "Id": 3,
  "Lastname": "Dirt"
}

This code demonstrates that only the checked attributes are copied over if they are different.

Typescript Playground

Answer 2

As previously stated in my comment, a helper type can be created to iterate over any type and convert it into an object with its attributes as booleans for the "isActive" part:

interface User {
  Id: number;
  FirstName: string;
  Lastname: string;
  Age: number;
}

type ToBooleanType<T> = {
  [P in keyof T]: boolean;
};

function copyIfAccepted<T extends object>(source: T, dest: T, checks: ToBooleanType<T>) {
  for (const key in source) {
    const sourceValue = source[key];
    const destValue = dest[key];
    const isAccepted = checks[key];

    if (isAccepted && sourceValue !== destValue) {
      dest[key] = sourceValue;
    }
  }
}
const user1: User = { Age: 21, FirstName: 'Joe', Id: 1, Lastname: 'Dirt' };
const user2: User = { Age: 26, FirstName: 'Jane', Id: 3, Lastname: 'Doe' };

copyIfAccepted(user1, user2, { Id: false, Age: true, FirstName: false, Lastname: true });

console.log(user1, user2);

Output:

[LOG]: {
  "Age": 21,
  "FirstName": "Joe",
  "Id": 1,
  "Lastname": "Dirt"
},  {
  "Age": 21,
  "FirstName": "Jane",
  "Id": 3,
  "Lastname": "Dirt"
}

This code demonstrates that only the checked attributes are copied over if they are different.

Typescript Playground

Assign a true or false value to every attribute of an object

Answer №1

Similar questions

What is the best way to retrieve a variable that has been exported from a page and access it in _

Steps for accessing the camera within a custom Ionic app

Create collaborative documents with serverless TypeScript extension

Is tsconfig.json necessary for JS libraries without TypeScript to include a .d.ts file when shipping?

TypeScript: By providing a variable CLASS as an argument to a function, automatically determine the return type to be an object of the specified class without any additional information

Getting a precise item in JSON with varied key signatures

Discovering the generic type from an optional parameter within a constructor

Using React.ReactNode as an argument in Storybook

Misunderstanding the concept of always being right

Creating a dynamic TypeScript signature that includes an optional argument

What is the best way to access the input element of ng-content from the parent component?

How to effectively merge DefaultTheme with styled-components in TypeScript?

Categories for the Promise.all() function

Only JSON objects with a boolean value of true will be returned

When creating utility classes, is it beneficial to offer a non-mutable API to facilitate their integration with frameworks such as React?

Exploring the concept of relative routing within Angular

BaQend is all set to go as it initializes, just make sure to verify the user's login

Passing along the mouse event to the containing canvas element that utilizes chart.js

Numerous toggle classes available

Encountering issues when trying to import const enums in a webpack project using babel