Update all the Values in an Object using JavaScript

# Update all the Values in an Object in JavaScript

To update all the values in an object:

1. Use the Object.keys() method to get an array of the object's keys.
2. Iterate over the array using the forEach() method and update each value.
3. After the last iteration, all the values in the object will be updated.

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const obj = {
  country: 'Chile',
  city: 'Santiago',
  address: 'Example',
  name: 'bobby hadz',
};

Object.keys(obj).forEach(key => {
  obj[key] = '';
});

// 👇️ { country: '', city: '', address: '', name: '' }
console.log(obj);

We used the Object.keys method to get an array of the object's keys.

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const obj = {
  country: 'Chile',
  city: 'Santiago',
  address: 'Example',
  name: 'bobby hadz',
};

// 👇️ [ 'country', 'city', 'address', 'name' ]
console.log(Object.keys(obj));

The next step is to iterate over the array of keys using the Array.forEach method.

The function we passed to the forEach() method gets called for each element of the array and gets passed 3 arguments:

1. the array element
2. the index
3. the array

If you need to use the index, assign the second parameter of the callback function to a variable.

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const obj = {
  country: 'Chile',
  city: 'Santiago',
  address: 'Example',
};

Object.keys(obj).forEach((key, index) => {
  obj[key] = obj[key] + index;
});

// 👇️ {country: 'Chile0', city: 'Santiago1', address: 'Example2'}
console.log(obj);

# Conditionally update the values in an object

You can also check for a condition in an if statement before updating the object's values.

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const obj = {
  name: 'bobby hadz',
  num1: 9,
  num2: 19,
  num3: 29,
};


Object.keys(obj).forEach((key, index) => {
  if (typeof obj[key] === 'number' && obj[key] > 10) {
    obj[key] = 0;
  }
});

// 👇️ { name: 'bobby hadz', num1: 9, num2: 0, num3: 0 }
console.log(obj);

The code sample checks if each key has a value of type number and if the value is greater than 10.

If both conditions are met, the key's value gets set to 0.

You can also use the Object.entries() method instead of Object.keys().

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const obj = {
  name: 'bobby hadz',
  num1: 9,
  num2: 19,
  num3: 29,
};

Object.entries(obj).forEach(([key, value], index) => {
  if (typeof obj[key] === 'number' && value > 10) {
    obj[key] = 0;
  }
});

// 👇️ { name: 'bobby hadz', num1: 9, num2: 0, num3: 0 }
console.log(obj);

The Object.entries method returns an array of the given object's key-value pairs.

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const obj = {
  name: 'bobby hadz',
  num1: 9,
  num2: 19,
  num3: 29,
};

// [
//   [ 'name', 'bobby hadz' ],
//   [ 'num1', 9 ],
//   [ 'num2', 19 ],
//   [ 'num3', 29 ]
// ]
console.log(Object.entries(obj));

The first element in each array is the key and the second is the value.

# Update all the Values in an Object without Mutation

This is a three-step process:

1. Use the Object.keys() method to get an array of the object's keys.
2. Use the reduce() method to iterate over the array.
3. On each iteration, return a new object that contains the values from the previous iteration and the updated value.

Copied!
const obj = {
  country: 'Chile',
  city: 'Santiago',
  address: 'Example',
  name: 'bobby hadz',
};

const newObj = Object.keys(obj).reduce((accumulator, key) => {
  return {...accumulator, [key]: ''};
}, {});

// { country: '', city: '', address: '', name: '' }
console.log(newObj);

// {
//   country: 'Chile',
//   city: 'Santiago',
//   address: 'Example',
//   name: 'bobby hadz'
// }
console.log(obj);

We got an array of the object's keys using the Object.keys() method.

The function we passed to the Array.reduce method gets called for each element in the array.

We initialized the accumulator variable to an empty object because that's what we passed as the second argument to the reduce() method.

On each iteration, we use the spread syntax (...) to unpack the key-value pairs of the object into a new object and update the current value.

The value we return from the callback function gets passed as the accumulator on the next iteration.

This approach doesn't change the values of the original object, it returns a new object.

# Conditionally update the values in an object using reduce()

You can also conditionally update the values in an object using reduce().

Copied!
const obj = {
  name: 'bobby hadz',
  num1: 9,
  num2: 19,
  num3: 29,
};

const newObj = Object.keys(obj).reduce((accumulator, key) => {
  if (typeof key[obj] === 'number' && key[obj] > 10) {
    return {...accumulator, [key]: 0};
  }

  return {...accumulator, [key]: obj[key]};
}, {});

// 👇️ { name: 'bobby hadz', num1: 9, num2: 19, num3: 29 }
console.log(newObj);

If the current key is a number and is greater than 10, we set it to 0.

Otherwise, we return the key as is.

# Update all the Values in an Object using for...of

This is a three-step process:

1. Use the Object.keys() method to get an array of the object's keys.
2. Use a for...of loop to iterate over the array.
3. Update the value of each key.

Copied!
const obj = {
  country: 'Chile',
  city: 'Santiago',
  address: 'Example',
  name: 'bobby hadz',
};

for (const key of Object.keys(obj)) {
  obj[key] = '';
}

// 👇️ { country: '', city: '', address: '', name: '' }
console.log(obj);

The for...of statement is used to loop over iterable objects like arrays, strings, Map, Set and NodeList objects and generators.

On each iteration, we set the value of the current key to an empty string.

This approach mutates the original object.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Convert an Array of Objects to an Array of Values in JS
• Convert an Array's Values to Object Keys in JavaScript
• Convert an Object's Values or Keys to an Array in JavaScript
• How to Sum a Property in an Array of Objects in JavaScript
• Remove Null or Undefined Values from Object in Javascript