freeCodeCamp/curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/use-model.findbyid-to-search-your-database-by-id.english.md

---
id: 587d7fb7367417b2b2512c0d
title: Use model.findById() to Search Your Database By _id
challengeType: 2
---

## Description
<section id='description'>
When saving a document, mongodb automatically adds the field _id, and set it to a unique alphanumeric key. Searching by _id is an extremely frequent operation, so mongoose provides a dedicated method for it. Find the (only!!) person who has the given _id using Model.findById() -> Person. Use the function argument personId as search key.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: Find an item by Id should succeed
    testString: "getUserInput => $.get(getUserInput('url') + '/_api/find-by-id').then(data => { assert.equal(data.name, 'test', 'item.name is not what expected'); assert.equal(data.age, 0, 'item.age is not what expected'); assert.deepEqual(data.favoriteFoods, ['none'], 'item.favoriteFoods is not what expected'); assert.equal(data.__v, 0, 'The item should be not previously edited'); }, xhr => { throw new Error(xhr.responseText); })"
```

</section>

## Challenge Seed
<section id='challengeSeed'>

</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>