Selecting an object dynamically to add a new property in JavaScript

Question

Selecting an object dynamically to add a new property in JavaScript

I am faced with a scenario where I have two objects and I need to add new properties to them. The challenge is that I want to be able to choose which object to work with first before adding the new properties. Here's the proposed logic :

let customizeObjects = (function() {

    // Define the Two Objects
    let university = {}
    let Person = {}

    let addNewPropTo = (objName, newProp) => {
         return objName[newProp] = null;  // Issue in logic 1
    }
    
    let getProperties = (objName) => {
       return Object.getOwnPropertyNames(objName)
    }

    return {
       addNewPropTo,
       getProperties
    }

})();

customizeObjects.addNewPropTo('Person', 'Age'); // Issue in logic 2
customizeObjects.getProperties(Person) // Expected Output : Person = { Age : null }

javascript typescript

Answer 1

Answer №1

When encountering the error message in logic fail 1, it indicates that an attempt is being made to add a property to the string objName, rather than the intended object.
In this case, select one of your objects.

let AddNewPropTo = ( objName , new_objProp ) => {
  if (objName === 'Person') {
    Person[new_objProp] = null
    return Person
  }
  if (objName === 'university') {
    university[new_objProp] = null
    return university
  } 
}

The issue in the second logic fail seems to be a simple oversight as the return value is not saved.

const Person = myFn.AddNewPropTo('Person','Age'); // logic fail 2
const props = myFn.getProps(Person) // Desired Output : Person = { Age : null }
console.log(props)

To make the process more dynamic, consider the following approach:

let university = {}
let Person = {}
const map = {
  'Person': Person,
  'university': university
}

let AddNewPropTo = ( objName , new_objProp ) => {
  let obj = map[objName]
  if (obj) {
    obj[new_objProp] = null
    return obj
  }
  return {}
}

Answer 2

When encountering the error message in logic fail 1, it indicates that an attempt is being made to add a property to the string objName, rather than the intended object.
In this case, select one of your objects.

let AddNewPropTo = ( objName , new_objProp ) => {
  if (objName === 'Person') {
    Person[new_objProp] = null
    return Person
  }
  if (objName === 'university') {
    university[new_objProp] = null
    return university
  } 
}

The issue in the second logic fail seems to be a simple oversight as the return value is not saved.

const Person = myFn.AddNewPropTo('Person','Age'); // logic fail 2
const props = myFn.getProps(Person) // Desired Output : Person = { Age : null }
console.log(props)

To make the process more dynamic, consider the following approach:

let university = {}
let Person = {}
const map = {
  'Person': Person,
  'university': university
}

let AddNewPropTo = ( objName , new_objProp ) => {
  let obj = map[objName]
  if (obj) {
    obj[new_objProp] = null
    return obj
  }
  return {}
}

Answer 3

Answer №2

I may not be well-versed in typescript, but I was able to achieve the desired result just like you wanted.

Feel free to take a look at this Fiddle for more information.

Here is the code snippet:

let Person = {}

function AddNewPropTo( objName , new_objProp ) {
     return objName[new_objProp] = 1;  // logic fail 1
}
function getProps  (objName) {
   return Object.getOwnPropertyNames(objName);
}


 AddNewPropTo(Person,'Age'); 
 console.log(getProps(Person)) ; //returns ['Age']

Answer 4

I may not be well-versed in typescript, but I was able to achieve the desired result just like you wanted.

Feel free to take a look at this Fiddle for more information.

Here is the code snippet:

let Person = {}

function AddNewPropTo( objName , new_objProp ) {
     return objName[new_objProp] = 1;  // logic fail 1
}
function getProps  (objName) {
   return Object.getOwnPropertyNames(objName);
}


 AddNewPropTo(Person,'Age'); 
 console.log(getProps(Person)) ; //returns ['Age']

Selecting an object dynamically to add a new property in JavaScript

Answer №1

Answer №2

Similar questions

Creating unique identifiers using node.js

Ensuring the child div's height does not overflow beyond the parent div

An assortment of diverse data types in TypeScript arrays

Interacting with a form input by triggering the onChange event

Changing the parent scope from the child component does not automatically reflect changes in an ng-repeat

Determining the specific condition that failed in a series of condition checks within a TypeScript script

Public directory assets not accessible

Selecting an option with a specific index in Angular 2 RC2

The autocomplete feature is not displaying the data in the Bootstrap modal, only the list is visible

axios interceptor - delay the request until the cookie API call is completed, and proceed only after that

Tips for converting NULL% to 0%

Managing Import Structure in Turborepo/Typescript Package

Create a responsive iframe that expands to fullscreen when a button is clicked

Not motivated to write HTML content

Angular's minimum date validation is not accurate for dates prior to the year 1901

Receiving multiple NodeJS Responses through AJAX for a single request

Pulling information from a JSON file using Angular 2

Make sure to load all necessary resources prior to loading the webpage

Utilizing the Vuetify pagination feature in your project

Changing the port number for a gulp-angular project with loopback REST API: A step-by-step guide