Remove duplicate values from an array by applying a specific condition

Question

Remove duplicate values from an array by applying a specific condition

I am encountering an issue with an array that contains duplicate elements

let myArray=[
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: "d-2"},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""}
     {role: "role-5", deviceId: ""}
]

My goal is to eliminate the duplicate roles from the array, keeping only one role for each distinct role-value pair where the deviceId is not empty(""), and retain only one duplicate if the deviceId is empty in this manner.

myArray=[
         {role: "role-1", deviceId: "d-1"},
         {role: "role-2", deviceId: "d-2"},
         {role: "role-3", deviceId: "d-3"}
         {role: "role-4", deviceId: ""}
         {role: "role-5", deviceId: ""}

 ]

The function I have written attempts to solve this issue:

function dedupeByKey(arr, key) {
  const temp = arr.map(el => el[key]);
  return arr.filter((el, i) =>
    temp.indexOf(el[key]) === i
  );
}

console.log(dedupeByKey(myArray, 'role'));

However, the current implementation does not prioritize deviceIds with values, resulting in roles with empty(deviceId) being included. How can I address this issue?

javascript arrays

Answer 1

Answer №1

To easily handle objects in JavaScript, you can utilize the reduce method with a default object and then convert it to an array if needed.

let myArray = [
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: "d-2"},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""},
     {role: "role-5", deviceId: ""}
]

const result = myArray.reduce((accumulator, currentItem) => {
  if (accumulator[currentItem.role]) return accumulator // skip iteration if deviceId already exists
  accumulator[currentItem.role] = currentItem.deviceId // add deviceId if it does not exist
  return accumulator
}, {})

let finalArray = Object.keys(result).map(key => { return { role: key, deviceId: result[key] }})

console.log(finalArray)

Answer 2

To easily handle objects in JavaScript, you can utilize the reduce method with a default object and then convert it to an array if needed.

let myArray = [
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: "d-2"},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""},
     {role: "role-5", deviceId: ""}
]

const result = myArray.reduce((accumulator, currentItem) => {
  if (accumulator[currentItem.role]) return accumulator // skip iteration if deviceId already exists
  accumulator[currentItem.role] = currentItem.deviceId // add deviceId if it does not exist
  return accumulator
}, {})

let finalArray = Object.keys(result).map(key => { return { role: key, deviceId: result[key] }})

console.log(finalArray)

Answer 3

Answer №2

To transform a unique role to an object and condense it into an array, utilize the code snippet below:

let myArray = [
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: "d-2"},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""},
     {role: "role-5", deviceId: ""}
];

var uniqueObj = myArray.reduce(function(acc, item) {
  var deviceId = acc[item.role] && acc[item.role].deviceId || item.deviceId;
  acc[item.role] = item;
  acc[item.role].deviceId = deviceId;
  return acc;
}, {});

var result = Object.keys(uniqueObj).reduce(function(acc2, item) {
  acc2.push(uniqueObj[item]);
  return acc2;
}, []);

console.log(result);

Answer 4

To transform a unique role to an object and condense it into an array, utilize the code snippet below:

let myArray = [
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: "d-2"},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""},
     {role: "role-5", deviceId: ""}
];

var uniqueObj = myArray.reduce(function(acc, item) {
  var deviceId = acc[item.role] && acc[item.role].deviceId || item.deviceId;
  acc[item.role] = item;
  acc[item.role].deviceId = deviceId;
  return acc;
}, {});

var result = Object.keys(uniqueObj).reduce(function(acc2, item) {
  acc2.push(uniqueObj[item]);
  return acc2;
}, []);

console.log(result);

Answer 5

Answer №3

One approach is to use a filter function and search ahead in the array for duplicates to determine whether to keep or remove the index.

const myArray= [
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: ""},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""},
     {role: "role-5", deviceId: ""}
]
  
const cleanArray = myArray.filter( (item,index,array) => {
  if ( item.deviceId === "") {
    // Filter out items with duplicate roles found later in the array
    return !array.some((i,idx) => i.role === item.role && idx > index )
  }
  return true 
})

// Sort the cleaned array for presentation
const sortedArray = cleanArray.sort( (curr, next) => curr.role >  next.role? 1:-1);

console.log(sortedArray)

Answer 6

One approach is to use a filter function and search ahead in the array for duplicates to determine whether to keep or remove the index.

const myArray= [
     {role: "role-1", deviceId: ""},
     {role: "role-2", deviceId: ""},
     {role: "role-3", deviceId: "d-3"},
     {role: "role-1", deviceId: "d-1"},
     {role: "role-2", deviceId: ""},
     {role: "role-4", deviceId: ""},
     {role: "role-5", deviceId: ""}
]
  
const cleanArray = myArray.filter( (item,index,array) => {
  if ( item.deviceId === "") {
    // Filter out items with duplicate roles found later in the array
    return !array.some((i,idx) => i.role === item.role && idx > index )
  }
  return true 
})

// Sort the cleaned array for presentation
const sortedArray = cleanArray.sort( (curr, next) => curr.role >  next.role? 1:-1);

console.log(sortedArray)

Answer 7

Answer №4

To efficiently organize the data by `role` and then select the first one with a corresponding `deviceId`, you can utilize the following code snippet:

  function groupBy(array, key) {
    const result = { };
    for(const el of array) {
      if(!result[ el[key] ]) result[ el[key] ] = [];
       result[ el[key] ].push(el);
   }
  return result;
}

const resultArray = [];
const groupedData = groupBy(myArray, "role");
for(const group of Object.values(groupedData)) {
  resultArray.push(group.find(item => item.deviceId) || group[0]);
}

Answer 8

To efficiently organize the data by `role` and then select the first one with a corresponding `deviceId`, you can utilize the following code snippet:

  function groupBy(array, key) {
    const result = { };
    for(const el of array) {
      if(!result[ el[key] ]) result[ el[key] ] = [];
       result[ el[key] ].push(el);
   }
  return result;
}

const resultArray = [];
const groupedData = groupBy(myArray, "role");
for(const group of Object.values(groupedData)) {
  resultArray.push(group.find(item => item.deviceId) || group[0]);
}

Remove duplicate values from an array by applying a specific condition

Answer №1

Answer №2

Answer №3

Answer №4

Similar questions

Utilizing npm packages from third-party sources within a custom extension for personal use (not intended for distribution)

Finding out whether the current date falls between a startDate and endDate within a nested object in mongoose can be done by using a specific method

Remove numerous entries from the WordPress database by selecting multiple checkboxes

Hide Navbar when clicking on menu item

You are not able to access the instance member in Jest

Tips for integrating an arrow function as a property in a functional programming approach using JavaScript or TypeScript

My changes to the HTML file are not being reflected in the browser, even after clearing the cache. This is happening in an Angular and Node.js application

While loop not yielding immediate result with asynchronous function

Properly executing a for loop

RegEx not triggering Mongoose hooks

Tips for utilizing nested filters to identify when there is a single list item and its child is specifically a <strong> tag

Tips for accessing a value in a multidimensional json array without the key in JavaScript/jQuery?

A collection nested inside another collection

Is it possible to bypass the standard syntax and manipulate geometry buffers directly in three.js in order to achieve improved performance?

Leveraging jQuery and Ajax for extracting and transmitting parameters within href links

Utilizing a custom handler for Jquery Oembed functionality

Discovering the correct method to access a slug from an API endpoint in NextJS v14's "App Router"

js.executeScript produces a Unexpected identifier error

Is it possible to perform bulk deletes using Sequelize?

Tips for accessing information from different sources within Vue 3