**Installation**: `npm install sift`, or `yarn add sift`
## Sift is a tiny library for using MongoDB queries in Javascript
[](https://secure.travis-ci.org/crcn/sift.js)
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**For extended documentation, checkout http://docs.mongodb.org/manual/reference/operator/query/**
## Features:
- Supported operators: [\$in](#in), [\$nin](#nin), [\$exists](#exists), [\$gte](#gte), [\$gt](#gt), [\$lte](#lte), [\$lt](#lt), [\$eq](#eq), [\$ne](#ne), [\$mod](#mod), [\$all](#all), [\$and](#and), [\$or](#or), [\$nor](#nor), [\$not](#not), [\$size](#size), [\$type](#type), [\$regex](#regex), [\$where](#where), [\$elemMatch](#elemmatch)
- Regexp searches
- Supports node.js, and web
- Custom Operations
- Tree-shaking (omitting functionality from web app bundles)
## Examples
```javascript
import sift from "sift";
//intersecting arrays
const result1 = ["hello", "sifted", "array!"].filter(
sift({ $in: ["hello", "world"] })
); //['hello']
//regexp filter
const result2 = ["craig", "john", "jake"].filter(sift(/^j/)); //['john','jake']
// function filter
const testFilter = sift({
//you can also filter against functions
name: function(value) {
return value.length == 5;
}
});
const result3 = [
{
name: "craig"
},
{
name: "john"
},
{
name: "jake"
}
].filter(testFilter); // filtered: [{ name: 'craig' }]
//you can test *single values* against your custom sifter
testFilter({ name: "sarah" }); //true
testFilter({ name: "tim" }); //false
```
## API
### sift(query: MongoQuery, options?: Options): Function
Creates a filter with all of the built-in MongoDB query operations.
- `query` - the filter to use against the target array
- `options`
- `operations` - [custom operations](#custom-operations)
- `compare` - compares difference between two values
Example:
```javascript
import sift from "sift";
const test = sift({ $gt: 5 }));
console.log(test(6)); // true
console.log(test(4)); // false
[3, 4, 5, 6, 7].filter(sift({ $exists: true })); // [6, 7]
```
### createQueryTester(query: Query, options?: Options): Function
Creates a filter function **without** built-in MongoDB query operations. This is useful
if you're looking to omit certain operations from application bundles. See [Omitting built-in operations](#omitting-built-in-operations) for more info.
```javascript
import { createQueryTester, $eq, $in } from "sift";
const filter = createQueryTester({ $eq: 5 }, { operations: { $eq, $in } });
```
### createEqualsOperation(params: any, ownerQuery: Query, options: Options): Operation
Used for [custom operations](#custom-operations).
```javascript
import { createQueryTester, createEqualsOperation, $eq, $in } from "sift";
const filter = createQueryTester(
{ $mod: 5 },
{
operations: {
$something(mod, ownerQuery, options) {
return createEqualsOperation(
value => value % mod === 0,
ownerQuery,
options
);
}
}
}
);
filter(10); // true
filter(11); // false
```
## Supported Operators
See MongoDB's [advanced queries](http://www.mongodb.org/display/DOCS/Advanced+Queries) for more info.
### \$in
array value must be _\$in_ the given query:
Intersecting two arrays:
```javascript
//filtered: ['Brazil']
["Brazil", "Haiti", "Peru", "Chile"].filter(
sift({ $in: ["Costa Rica", "Brazil"] })
);
```
Here's another example. This acts more like the \$or operator:
```javascript
[{ name: "Craig", location: "Brazil" }].filter(
sift({ location: { $in: ["Costa Rica", "Brazil"] } })
);
```
### \$nin
Opposite of \$in:
```javascript
//filtered: ['Haiti','Peru','Chile']
["Brazil", "Haiti", "Peru", "Chile"].filter(
sift({ $nin: ["Costa Rica", "Brazil"] })
);
```
### \$exists
Checks if whether a value exists:
```javascript
//filtered: ['Craig','Tim']
sift({ $exists: true })(["Craig", null, "Tim"]);
```
You can also filter out values that don't exist
```javascript
//filtered: [{ name: "Tim" }]
[{ name: "Craig", city: "Minneapolis" }, { name: "Tim" }].filter(
sift({ city: { $exists: false } })
);
```
### \$gte
Checks if a number is >= value:
```javascript
//filtered: [2, 3]
[0, 1, 2, 3].filter(sift({ $gte: 2 }));
```
### \$gt
Checks if a number is > value:
```javascript
//filtered: [3]
[0, 1, 2, 3].filter(sift({ $gt: 2 }));
```
### \$lte
Checks if a number is <= value.
```javascript
//filtered: [0, 1, 2]
[0, 1, 2, 3].filter(sift({ $lte: 2 }));
```
### \$lt
Checks if number is < value.
```javascript
//filtered: [0, 1]
[0, 1, 2, 3].filter(sift({ $lt: 2 }));
```
### \$eq
Checks if `query === value`. Note that **\$eq can be omitted**. For **\$eq**, and **\$ne**
```javascript
//filtered: [{ state: 'MN' }]
[{ state: "MN" }, { state: "CA" }, { state: "WI" }].filter(
sift({ state: { $eq: "MN" } })
);
```
Or:
```javascript
//filtered: [{ state: 'MN' }]
[{ state: "MN" }, { state: "CA" }, { state: "WI" }].filter(
sift({ state: "MN" })
);
```
### \$ne
Checks if `query !== value`.
```javascript
//filtered: [{ state: 'CA' }, { state: 'WI'}]
[{ state: "MN" }, { state: "CA" }, { state: "WI" }].filter(
sift({ state: { $ne: "MN" } })
);
```
### \$mod
Modulus:
```javascript
//filtered: [300, 600]
[100, 200, 300, 400, 500, 600].filter(sift({ $mod: [3, 0] }));
```
### \$all
values must match **everything** in array:
```javascript
//filtered: [ { tags: ['books','programming','travel' ]} ]
[
{ tags: ["books", "programming", "travel"] },
{ tags: ["travel", "cooking"] }
].filter(sift({ tags: { $all: ["books", "programming"] } }));
```
### \$and
ability to use an array of expressions. All expressions must test true.
```javascript
//filtered: [ { name: 'Craig', state: 'MN' }]
[
{ name: "Craig", state: "MN" },
{ name: "Tim", state: "MN" },
{ name: "Joe", state: "CA" }
].filter(sift({ $and: [{ name: "Craig" }, { state: "MN" }] }));
```
### \$or
OR array of expressions.
```javascript
//filtered: [ { name: 'Craig', state: 'MN' }, { name: 'Tim', state: 'MN' }]
[
{ name: "Craig", state: "MN" },
{ name: "Tim", state: "MN" },
{ name: "Joe", state: "CA" }
].filter(sift({ $or: [{ name: "Craig" }, { state: "MN" }] }));
```
### \$nor
opposite of or:
```javascript
//filtered: [{ name: 'Joe', state: 'CA' }]
[
{ name: "Craig", state: "MN" },
{ name: "Tim", state: "MN" },
{ name: "Joe", state: "CA" }
].filter(sift({ $nor: [{ name: "Craig" }, { state: "MN" }] }));
```
### \$size
Matches an array - must match given size:
```javascript
//filtered: ['food','cooking']
[{ tags: ["food", "cooking"] }, { tags: ["traveling"] }].filter(
sift({ tags: { $size: 2 } })
);
```
### \$type
Matches a values based on the type
```javascript
[new Date(), 4342, "hello world"].filter(sift({ $type: Date })); //returns single date
[new Date(), 4342, "hello world"].filter(sift({ $type: String })); //returns ['hello world']
```
### \$regex
Matches values based on the given regular expression
```javascript
["frank", "fred", "sam", "frost"].filter(
sift({ $regex: /^f/i, $nin: ["frank"] })
); // ["fred", "frost"]
["frank", "fred", "sam", "frost"].filter(
sift({ $regex: "^f", $options: "i", $nin: ["frank"] })
); // ["fred", "frost"]
```
### \$where
Matches based on some javascript comparison
```javascript
[{ name: "frank" }, { name: "joe" }].filter(
sift({ $where: "this.name === 'frank'" })
); // ["frank"]
[{ name: "frank" }, { name: "joe" }].filter(
sift({
$where: function() {
return this.name === "frank";
}
})
); // ["frank"]
```
### \$elemMatch
Matches elements of array
```javascript
var bills = [
{
month: "july",
casts: [
{
id: 1,
value: 200
},
{
id: 2,
value: 1000
}
]
},
{
month: "august",
casts: [
{
id: 3,
value: 1000
},
{
id: 4,
value: 4000
}
]
}
];
var result = bills.filter(
sift({
casts: {
$elemMatch: {
value: { $gt: 1000 }
}
}
})
); // {month:'august', casts:[{id:3, value: 1000},{id: 4, value: 4000}]}
```
### \$not
Not expression:
```javascript
["craig", "tim", "jake"].filter(sift({ $not: { $in: ["craig", "tim"] } })); //['jake']
["craig", "tim", "jake"].filter(sift({ $not: { $size: 5 } })); //['tim','jake']
```
### Date comparison
Mongodb allows you to do date comparisons like so:
```javascript
db.collection.find({ createdAt: { $gte: "2018-03-22T06:00:00Z" } });
```
In Sift, you'll need to specify a Date object:
```javascript
collection.find(
sift({ createdAt: { $gte: new Date("2018-03-22T06:00:00Z") } })
);
```
## Custom behavior
Sift works like MongoDB out of the box, but you're also able to modify the behavior to suite your needs.
#### Custom operations
You can register your own custom operations. Here's an example:
```javascript
import sift, { createEqualsOperation } from "sift";
var filter = sift(
{
$customMod: 2
},
{
operations: {
$customMod(params, ownerQuery, options) {
return createEqualsOperation(
value => value % params !== 0,
ownerQuery,
options
);
}
}
}
);
[1, 2, 3, 4, 5].filter(filter); // 1, 3, 5
```
#### Omitting built-in operations
You can create a filter function that omits the built-in operations like so:
```javascript
import { createQueryTester, $in, $all, $nin, $lt } from "sift";
const test = createQueryTester(
{
$eq: 10
},
{ operations: { $in, $all, $nin, $lt } }
);
[1, 2, 3, 4, 10].filter(test);
```
For bundlers like `Webpack` and `Rollup`, operations that aren't used are omitted from application bundles via tree-shaking.
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