JavaScript: Convert an object into a list of pairs

JavaScript Object: Exercise-15 with Solution

Write a JavaScript function to convert an object into a list of '[key, value]' pairs.

Sample Solution: -

HTML Code:

<!DOCTYPE html>
  <meta charset="utf-8">
  <title>JavaScript function to convert an object into a list of pairs.</title>


JavaScript Code:

function key_value_pairs(obj) 
    var keys = _keys(obj);
    var length = keys.length;
    var pairs = Array(length);
    for (var i = 0; i < length; i++) 
      pairs[i] = [keys[i], obj[keys[i]]];
    return pairs;

function _keys(obj) 
    if (!isObject(obj)) return [];
    if (Object.keys) return Object.keys(obj);
    var keys = [];
    for (var key in obj) if (_.has(obj, key)) keys.push(key);
    return keys;
function isObject(obj) 
    var type = typeof obj;
    return type === 'function' || type === 'object' && !!obj;
console.log(key_value_pairs({red: "#FF0000", green: "#00FF00", white: "#FFFFFF"}));

Sample Output:



Flowchart: JavaScript:- Convert an object into a list of pairs

Live Demo:

See the Pen javascript-object-exercise-15 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript function to get a copy of the object where the keys have become the values and the values the keys.

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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";


includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv