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JavaScript: Remove the key-value pairs corresponding to the given keys from an object

JavaScript fundamental (ES6 Syntax): Exercise-39 with Solution

Write a JavaScript program to remove the key-value pairs corresponding to the given keys from an object.

  • Use Object.keys(), Array.prototype.filter() and Array.prototype.includes() to remove the provided keys.
  • Use Array.prototype.reduce() to convert the filtered keys back to an object with the corresponding key-value pairs.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const omit = (obj, arr) =>
  Object.keys(obj)
    .filter(k => !arr.includes(k))
    .reduce((acc, key) => ((acc[key] = obj[key]), acc), {});

console.log(omit({ a: 1, b: '2', c: 3 }, ['b']));
console.log(omit({ a: 1, b: 2, c: 3 }, ['c']));

Sample Output:

{"a":1,"c":3}
{"a":1,"b":2}

Pictorial Presentation:

JavaScript Fundamental: Remove the key-value pairs corresponding to the given keys from an object

Flowchart:

flowchart: Remove the key-value pairs corresponding to the given keys from an object

Live Demo:

See the Pen javascript-basic-exercise-1-39 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to pad a string on both sides with the specified character, if it's shorter than the specified length.
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JavaScript: Tips of the Day

How to remove a specific item from an array?

Find the index of the array element you want to remove using indexOf, and then remove that index with splice.

The splice() method changes the contents of an array by removing existing elements and/or adding new elements.

const array = [2, 5, 9];

console.log(array);

const index = array.indexOf(5);
if (index > -1) {
  array.splice(index, 1);
}

// array = [2, 9]
console.log(array);

The second parameter of splice is the number of elements to remove. Note that splice modifies the array in place and returns a new array containing the elements that have been removed.

For the reason of completeness, here are functions. The first function removes only a single occurrence (i.e. removing the first match of 5 from [2,5,9,1,5,8,5]), while the second function removes all occurrences:

function removeItemOnce(arr, value) {
  var index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  }
  return arr;
}

function removeItemAll(arr, value) {
  var i = 0;
  while (i < arr.length) {
    if (arr[i] === value) {
      arr.splice(i, 1);
    } else {
      ++i;
    }
  }
  return arr;
}
//Usage
console.log(removeItemOnce([2,5,9,1,5,8,5], 5))
console.log(removeItemAll([2,5,9,1,5,8,5], 5))

Ref: https://bit.ly/2N9nKRp