## validate objects & filter arrays with mongodb queries
[](https://secure.travis-ci.org/crcn/sift.js)
**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
- Function filtering
- sub object searching
- dot notation searching
- Supports node.js, and web
- Small (2 kb minified) library
- Custom Expressions
- filtering of immutable datastructures
## Node.js Examples
```javascript
import sift from 'sift';
//intersecting arrays
var sifted = sift({ $in: ['hello','world'] }, ['hello','sifted','array!']); //['hello']
//regexp filter
var sifted = sift(/^j/, ['craig','john','jake']); //['john','jake']
//A *sifter* is returned if the second parameter is omitted
var testQuery = sift({
//you can also filter against functions
name: function(value) {
return value.length == 5;
}
});
//filtered: [{ name: 'craig' }]
[{
name: 'craig',
},
{
name: 'john'
},
{
name: 'jake'
}].filter(testQuery);
//you can test *single values* against your custom sifter
testQuery({ name: 'sarah' }); //true
testQuery({ name: 'tim' }); //false\
```
## Browser Examples
```html
```
## API
### .sift(filter[, array][, selectorFn])
- `filter` - the filter to use against the target array
- `array` - sifts against target array. Without this, a function is returned
- `selectorFn` - selector for the values within the array.
With an array:
```javascript
sift({$exists:true}, ['craig',null]); //['craig']
```
Without an array, a sifter is returned:
```javascript
var siftExists = sift({$exists:true});
siftExists('craig'); //true
siftExists(null); //false
['craig',null].filter(siftExists); //['craig']
```
With a selector:
```javascript
var sifter = sift({$exists:true}, function(user) {
return !!user.name;
});
sifter([
{
name: "Craig"
},
{
name: null
}
])
```
With your sifter, you can also **test** values:
```javascript
siftExists(null); //false
siftExists('craig'); //true
```
## 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']
sift({ $in: ['Costa Rica','Brazil'] }, ['Brazil','Haiti','Peru','Chile']);
```
Here's another example. This acts more like the $or operator:
```javascript
sift({ location: { $in: ['Costa Rica','Brazil'] } }, [ { name: 'Craig', location: 'Brazil' } ]);
```
### $nin
Opposite of $in:
```javascript
//filtered: ['Haiti','Peru','Chile']
sift({ $nin: ['Costa Rica','Brazil'] }, ['Brazil','Haiti','Peru','Chile']);
```
### $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: 'Craig', city: 'Minneapolis' }]
sift({ city: { $exists: false } }, [ { name: 'Craig', city: 'Minneapolis' }, { name: 'Tim' }]);
```
### $gte
Checks if a number is >= value:
```javascript
//filtered: [2, 3]
sift({ $gte: 2 }, [0, 1, 2, 3]);
```
### $gt
Checks if a number is > value:
```javascript
//filtered: [3]
sift({ $gt: 2 }, [0, 1, 2, 3]);
```
### $lte
Checks if a number is <= value.
```javascript
//filtered: [0, 1, 2]
sift({ $lte: 2 }, [0, 1, 2, 3]);
```
### $lt
Checks if number is < value.
```javascript
//filtered: [0, 1]
sift({ $lt: 2 }, [0, 1, 2, 3]);
```
### $eq
Checks if `query === value`. Note that **$eq can be omitted**. For **$eq**, and **$ne**
```javascript
//filtered: [{ state: 'MN' }]
sift({ state: {$eq: 'MN' }}, [{ state: 'MN' }, { state: 'CA' }, { state: 'WI' }]);
```
Or:
```javascript
//filtered: [{ state: 'MN' }]
sift({ state: 'MN' }, [{ state: 'MN' }, { state: 'CA' }, { state: 'WI' }]);
```
### $ne
Checks if `query !== value`.
```javascript
//filtered: [{ state: 'CA' }, { state: 'WI'}]
sift({ state: {$ne: 'MN' }}, [{ state: 'MN' }, { state: 'CA' }, { state: 'WI' }]);
```
### $mod
Modulus:
```javascript
//filtered: [300, 600]
sift({ $mod: [3, 0] }, [100, 200, 300, 400, 500, 600]);
```
### $all
values must match **everything** in array:
```javascript
//filtered: [ { tags: ['books','programming','travel' ]} ]
sift({ tags: {$all: ['books','programming'] }}, [
{ tags: ['books','programming','travel' ] },
{ tags: ['travel','cooking'] } ]);
```
### $and
ability to use an array of expressions. All expressions must test true.
```javascript
//filtered: [ { name: 'Craig', state: 'MN' }]
sift({ $and: [ { name: 'Craig' }, { state: 'MN' } ] }, [
{ name: 'Craig', state: 'MN' },
{ name: 'Tim', state: 'MN' },
{ name: 'Joe', state: 'CA' } ]);
```
### $or
OR array of expressions.
```javascript
//filtered: [ { name: 'Craig', state: 'MN' }, { name: 'Tim', state: 'MN' }]
sift({ $or: [ { name: 'Craig' }, { state: 'MN' } ] }, [
{ name: 'Craig', state: 'MN' },
{ name: 'Tim', state: 'MN' },
{ name: 'Joe', state: 'CA' } ]);
```
### $nor
opposite of or:
```javascript
//filtered: [ { name: 'Tim', state: 'MN' }, { name: 'Joe', state: 'CA' }]
sift({ $nor: [ { name: 'Craig' }, { state: 'MN' } ] }, [
{ name: 'Craig', state: 'MN' },
{ name: 'Tim', state: 'MN' },
{ name: 'Joe', state: 'CA' } ]);
```
### $size
Matches an array - must match given size:
```javascript
//filtered: ['food','cooking']
sift({ tags: { $size: 2 } }, [ { tags: ['food','cooking'] }, { tags: ['traveling'] }]);
```
### $type
Matches a values based on the type
```javascript
sift({ $type: Date }, [new Date(), 4342, 'hello world']); //returns single date
sift({ $type: String }, [new Date(), 4342, 'hello world']); //returns ['hello world']
```
### $regex
Matches values based on the given regular expression
```javascript
sift({ $regex: /^f/i, $nin: ["frank"] }, ["frank", "fred", "sam", "frost"]); // ["fred", "frost"]
sift({ $regex: "^f", $options: "i", $nin: ["frank"] }, ["frank", "fred", "sam", "frost"]); // ["fred", "frost"]
```
### $where
Matches based on some javascript comparison
```javascript
sift({ $where: "this.name === 'frank'" }, [{name:'frank'},{name:'joe'}]); // ["frank"]
sift({
$where: function() {
return this.name === "frank"
}
}, [{name:'frank'},{name:'joe'}]); // ["frank"]
```
### $elemMatch
Matches elements of array
```javascript
var bills = [{
month: 'july',
casts: [{
id: 1,
value: 200
},{
id: 2,
value: 1000
}]
},
{
month: 'august',
casts: [{
id: 3,
value: 1000,
}, {
id: 4,
value: 4000
}]
}];
var result = sift({
casts: {$elemMatch:{
value: {$gt: 1000}
}}
}, bills); // {month:'august', casts:[{id:3, value: 1000},{id: 4, value: 4000}]}
```
### $not
Not expression:
```javascript
sift({$not:{$in:['craig','tim']}}, ['craig','tim','jake']); //['jake']
sift({$not:{$size:5}}, ['craig','tim','jake']); //['tim','jake']
```
## sub object Searching
```javascript
var people = [{
name: 'craig',
address: {
city: 'Minneapolis'
}
},
{
name: 'tim',
address: {
city: 'St. Paul'
}
}];
var sifted = sift({ address: { city: 'Minneapolis' }}, people); // count = 1
//or
var sifted = sift({'address.city': 'minneapolis'}, people);//count = 1
```
## Get index of first matching element
Get the index (0-based) of first matching element in target array. Returns `-1` if no match is found.
```javascript
import {indexOf as siftIndexOf} from 'sift';
var people = [{
name: 'craig',
address: {
city: 'Minneapolis'
}
},
{
name: 'tim',
address: {
city: 'St. Paul'
}
}];
var index = siftIndexOf({ address: { city: 'Minneapolis' }}, people); // index = 0
```