freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-an.../object-oriented-programming/iterate-over-all-properties.md

2.1 KiB

id title challengeType forumTopicId dashedName
587d7daf367417b2b2512b7d Iterate Over All Properties 1 301320 iterate-over-all-properties

--description--

You have now seen two kinds of properties: own properties and prototype properties. Own properties are defined directly on the object instance itself. And prototype properties are defined on the prototype.

function Bird(name) {
  this.name = name;  //own property
}

Bird.prototype.numLegs = 2; // prototype property

let duck = new Bird("Donald");

Here is how you add duck's own properties to the array ownProps and prototype properties to the array prototypeProps:

let ownProps = [];
let prototypeProps = [];

for (let property in duck) {
  if(duck.hasOwnProperty(property)) {
    ownProps.push(property);
  } else {
    prototypeProps.push(property);
  }
}

console.log(ownProps);
console.log(prototypeProps);

console.log(ownProps) would display ["name"] in the console, and console.log(prototypeProps) would display ["numLegs"].

--instructions--

Add all of the own properties of beagle to the array ownProps. Add all of the prototype properties of Dog to the array prototypeProps.

--hints--

The ownProps array should only contain name.

assert.deepEqual(ownProps, ['name']);

The prototypeProps array should only contain numLegs.

assert.deepEqual(prototypeProps, ['numLegs']);

You should solve this challenge without using the built in method Object.keys().

assert(!/\Object.keys/.test(code));

--seed--

--seed-contents--

function Dog(name) {
  this.name = name;
}

Dog.prototype.numLegs = 4;

let beagle = new Dog("Snoopy");

let ownProps = [];
let prototypeProps = [];

// Only change code below this line

--solutions--

function Dog(name) {
  this.name = name;
}

Dog.prototype.numLegs = 4;

let beagle = new Dog("Snoopy");

let ownProps = [];
let prototypeProps = [];
for (let prop in beagle) {
  if (beagle.hasOwnProperty(prop)) {
    ownProps.push(prop);
  } else {
    prototypeProps.push(prop);
  }
}