Convert an object to a Map in JavaScript

To convert an object to a Map, you can use the Object.entries() method. The Object.entries() function takes an object as an argument and returns an array of key-value pairs.

You can then pass the result to the Map() constructor to create a new Map object:

const user = {
  name: 'John Doe',
  age: 20,
  job: 'Engineer'
}

const kvPairs = Object.entries(user)

const map = new Map(kvPairs)
console.log(map)

// Map(3) { 'name' => 'John Doe', 'age' => 20, 'job' => 'Engineer' }

The Object.entries() converts an object into an array of key-value pairs that we pass to the Map() constructor to a new map:

const user = {
  name: 'John Doe',
  age: 20,
  job: 'Egineer'
}

const kvPairs = Object.entries(user)
console.log(kvPairs)

// [
//     [ 'name', 'John Doe' ],
//     [ 'age', 20 ],
//     [ 'job', 'Engineer' ]
// ]

An alternate approach is to use the Array.forEach() method to iterate over object keys and then add each key-value pair to the map using the Map.set() method:

const user = {
  name: 'John Doe',
  age: 20,
  job: 'Engineer'
}

const map = new Map()

Object.keys(user).forEach(key => {
  map.set(key, user[key])
})

console.log(map)
// Map(3) { 'name' => 'John Doe', 'age' => 20, 'job' => 'Engineer' }

If you want to convert the Map object back to an object, use the Object.fromEntries() method:

const map = new Map([
  ['name', 'John Doe'],
  ['age', 20],
  ['job', 'Engineer']
])

const user = Object.fromEntries(map)

console.log(user)
// { name: 'John Doe', age: 20, job: 'Engineer' }

Read this article to learn more about the Map object and how to use it to create collections of key-value pairs in JavaScript.

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