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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JavaScript: Tips of the Day


class Calc {
	constructor() {
		this.count = 0 

	increase() {
		this.count ++

const calc = new Calc()
new Calc().increase()


We set the variable calc equal to a new instance of the Calc class. Then, we instantiate a new instance of Calc, and invoke the increase method on this instance. Since the count property is within the constructor of the Calc class, the count property is not shared on the prototype of Calc. This means that the value of count has not been updated for the instance calc points to, count is still 0.

Ref: https://bit.ly/2Hcpkm6