47 lines
2.4 KiB
Markdown
47 lines
2.4 KiB
Markdown
---
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id: 587d7fb9367417b2b2512c12
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title: Chain Search Query Helpers to Narrow Search Results
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challengeType: 2
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forumTopicId: 301533
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---
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## Description
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<section id='description'>
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If you don’t pass the callback as the last argument to <code>Model.find()</code> (or to the other search methods), the query is not executed. You can store the query in a variable for later use. This kind of object enables you to build up a query using chaining syntax. The actual db search is executed when you finally chain the method <code>.exec()</code>. You always need to pass your callback to this last method. There are many query helpers, here we’ll use the most ‘famous’ ones.
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</section>
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## Instructions
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<section id='instructions'>
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Find people who like <code>burrito</code>. Sort them by name, limit the results to two documents, and hide their age. Chain <code>.find()</code>, <code>.sort()</code>, <code>.limit()</code>, <code>.select()</code>, and then <code>.exec()</code>. Pass the <code>done(err, data)</code> callback to <code>exec()</code>.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: Chaining query helpers should succeed
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testString: 'getUserInput => $.ajax({url: getUserInput(''url'') + ''/_api/query-tools'', type: ''POST'', contentType:''application/json'', data: JSON.stringify([{name: ''Pablo'', age: 26, favoriteFoods: [''burrito'', ''hot-dog'']}, {name: ''Bob'', age: 23, favoriteFoods: [''pizza'', ''nachos'']}, {name: ''Ashley'', age: 32, favoriteFoods: [''steak'', ''burrito'']}, {name: ''Mario'', age: 51, favoriteFoods: [''burrito'', ''prosciutto'']} ]) }).then(data => { assert.isArray(data, ''the response should be an Array''); assert.equal(data.length, 2, ''the data array length is not what expected''); assert.notProperty(data[0], ''age'', ''The returned first item has too many properties''); assert.equal(data[0].name, ''Ashley'', ''The returned first item name is not what expected''); assert.notProperty(data[1], ''age'', ''The returned second item has too many properties''); assert.equal(data[1].name, ''Mario'', ''The returned second item name is not what expected'');}, xhr => { throw new Error(xhr.responseText); })'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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</section>
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## Solution
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<section id='solution'>
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```js
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/**
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Backend challenges don't need solutions,
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because they would need to be tested against a full working project.
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Please check our contributing guidelines to learn more.
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*/
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```
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</section>
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