freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/object-oriented-programming/iterate-over-all-properties/index.md

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title: Iterate Over All Properties
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# Iterate Over All Properties

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## Problem Explanation

The method is to use a `for-in-loop` to iterate through every property in the object. Inside the loop you then check if the property is a `own-property` or a `prototype` and place it in the `ownProps[]` array or the `prototypeProps[]` array. Remember to `push` properties to the `beagle` object and not the `Dog` object to pass all test cases.


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## Solutions

<details><summary>Solution 1 (Click to Show/Hide)</summary>

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

Dog.prototype.numLegs = 4;

let beagle = new Dog("Snoopy");

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

// Add your code below this line
for (let property in beagle) {
  if (Dog.hasOwnProperty(property)) {
    ownProps.push(property);
  } else {
    prototypeProps.push(property);
  }
}
```
 

</details>