The sift npm package is a library that provides a way to use MongoDB-like query syntax for filtering, sorting, and manipulating JavaScript arrays and objects. It is commonly used for client-side querying of JSON data, in-memory database emulation, and other applications where MongoDB query semantics are desired without a database.

What are sift's main functionalities?

Filtering Arrays

This code sample demonstrates how to filter an array of objects to find elements where the age is greater than 18 and the name starts with the letter 'J'.

{"$and":[{"age":{"$gt":18}},{"name":{"$regex":"^J"}}]}

Sorting Arrays

This code sample shows how to sort an array of objects by the age property in ascending order.

{"$sort":{"age":1}}

Projection

This code sample illustrates how to create a projection of an array of objects, including only the name and age properties in the output.

{"$project":{"name":1,"age":1}}

Other packages similar to sift

Readme

Source

Installation: npm install sift, or yarn add sift

validate objects & filter arrays with mongodb queries

For extended documentation, checkout http://docs.mongodb.org/manual/reference/operator/query/

Features:

Supported operators: $in, $nin, $exists, $gte, $gt, $lte, $lt, $eq, $ne, $mod, $all, $and, $or, $nor, $not, $size, $type, $regex, $where, $elemMatch
Regexp searches
Function filtering
dot notation searching
Supports node.js, and web
Custom Operations

Node.js Examples

import sift from "sift";

//intersecting arrays
var result = ["hello", "sifted", "array!"].filter(
  sift({ $in: ["hello", "world"] })
); //['hello']

//regexp filter
var result = ["craig", "john", "jake"].filter(sift(/^j/)); //['john','jake']

// function filter
var testFilter = sift({
  //you can also filter against functions
  name: function(value) {
    return value.length == 5;
  }
});

var result = [
  {
    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

Browser Examples

<html>
  <head>
    <script
      src="https://raw.github.com/crcn/sift.js/master/sift.min.js"
      type="text/javascript"
    ></script>
    <script type="text/javascript">
      //regexp filter
      var sifted = ["craig", "john", "jake"].filter(sift(/^j/)); //['john','jake']
    </script>
  </head>
  <body></body>
</html>

API

.sift(query: MongoQuery, options?: SiftOptions): Function

query - the filter to use against the target array
options
- expressions - custom expressions
- compare - compares difference between two values

With an array:

["craig", null].filter(sift({ $exists: true })); //['craig']

Without an array, a sifter is returned:

var existsFilter = sift({ $exists: true });

existsFilter("craig"); //true
existsFilter(null); //false
["craig", null].filter(existsFilter); //['craig']

With your sifter, you can also test values:

siftExists(null); //false
siftExists("craig"); //true

Supported Operators:

See MongoDB's advanced queries for more info.

$in

array value must be $in the given query:

Intersecting two arrays:

//filtered: ['Brazil']
["Brazil", "Haiti", "Peru", "Chile"].filter(
  sift({ $in: ["Costa Rica", "Brazil"] })
);

Here's another example. This acts more like the $or operator:

[{ name: "Craig", location: "Brazil" }].filter(
  sift({ location: { $in: ["Costa Rica", "Brazil"] } })
);

$nin

Opposite of $in:

//filtered: ['Haiti','Peru','Chile']
["Brazil", "Haiti", "Peru", "Chile"].filter(
  sift({ $nin: ["Costa Rica", "Brazil"] })
);

$exists

Checks if whether a value exists:

//filtered: ['Craig','Tim']
sift({ $exists: true })(["Craig", null, "Tim"]);

You can also filter out values that don't exist

//filtered: [{ name: 'Craig', city: 'Minneapolis' }]
[{ name: "Craig", city: "Minneapolis" }, { name: "Tim" }].filter(
  sift({ city: { $exists: false } })
);

$gte

Checks if a number is >= value:

//filtered: [2, 3]
[0, 1, 2, 3].filter(sift({ $gte: 2 }));

$gt

Checks if a number is > value:

//filtered: [3]
[0, 1, 2, 3].filter(sift({ $gt: 2 }));

$lte

Checks if a number is <= value.

//filtered: [0, 1, 2]
[0, 1, 2, 3].filter(sift({ $lte: 2 }));

$lt

Checks if number is < value.

//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

//filtered: [{ state: 'MN' }]
[{ state: "MN" }, { state: "CA" }, { state: "WI" }].filter(
  sift({ state: { $eq: "MN" } })
);

Or:

//filtered: [{ state: 'MN' }]
[{ state: "MN" }, { state: "CA" }, { state: "WI" }].filter(
  sift({ state: "MN" })
);

$ne

Checks if query !== value.

//filtered: [{ state: 'CA' }, { state: 'WI'}]
[{ state: "MN" }, { state: "CA" }, { state: "WI" }].filter(
  sift({ state: { $ne: "MN" } })
);

$mod

Modulus:

//filtered: [300, 600]
[100, 200, 300, 400, 500, 600].filter(sift({ $mod: [3, 0] }));

$all

values must match everything in array:

//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.

//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.

//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:

//filtered: [ { name: 'Tim', state: 'MN' }, { 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:

//filtered: ['food','cooking']
[{ tags: ["food", "cooking"] }, { tags: ["traveling"] }].filter(
  sift({ tags: { $size: 2 } })
);

$type

Matches a values based on the type

[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

["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

[{ 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

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:

["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:

db.collection.find({ createdAt: { $gte: "2018-03-22T06:00:00Z" } });

In Sift, you'll need to specify a Date object:

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:

import sift, { EqualsOperation } from "sift";

var filter = sift(
  {
    $customMod: 2
  },
  {
    operations: {
      $customMod(params, ownerQuery, options) {
        return new EqualsOperation(
          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:

import { createQueryTester } from "sift";
import { $in, $all, $nin, $lt } from "sift/operations";
const test = createQueryTester(
  {
    $eq: 10
  },
  { $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.

FAQs

What is sift?

Is sift well maintained?

Last updated on 13 Jan 2020

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