77 lines
2.5 KiB
Markdown
77 lines
2.5 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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dashedName: chain-search-query-helpers-to-narrow-search-results
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---
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# --description--
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If you don’t pass the callback as the last argument to `Model.find()` (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 `.exec()`. You always need to pass your callback to this last method. There are many query helpers, here we'll use the most commonly used.
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# --instructions--
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Modify the `queryChain` function to find people who like the food specified by the variable named `foodToSearch`. Sort them by `name`, limit the results to two documents, and hide their age. Chain `.find()`, `.sort()`, `.limit()`, `.select()`, and then `.exec()`. Pass the `done(err, data)` callback to `exec()`.
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# --hints--
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Chaining query helpers should succeed
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```js
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(getUserInput) =>
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$.ajax({
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url: getUserInput('url') + '/_api/query-tools',
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type: 'POST',
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contentType: 'application/json',
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data: JSON.stringify([
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{ name: 'Pablo', age: 26, favoriteFoods: ['burrito', 'hot-dog'] },
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{ name: 'Bob', age: 23, favoriteFoods: ['pizza', 'nachos'] },
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{ name: 'Ashley', age: 32, favoriteFoods: ['steak', 'burrito'] },
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{ name: 'Mario', age: 51, favoriteFoods: ['burrito', 'prosciutto'] }
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])
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}).then(
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(data) => {
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assert.isArray(data, 'the response should be an Array');
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assert.equal(
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data.length,
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2,
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'the data array length is not what expected'
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);
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assert.notProperty(
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data[0],
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'age',
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'The returned first item has too many properties'
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);
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assert.equal(
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data[0].name,
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'Ashley',
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'The returned first item name is not what expected'
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);
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assert.notProperty(
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data[1],
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'age',
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'The returned second item has too many properties'
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);
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assert.equal(
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data[1].name,
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'Mario',
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'The returned second item name is not what expected'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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# --solutions--
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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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