pouchdb-find

by nolanlawson

nolanlawson / pouchdb-find

Easy-to-use query language for PouchDB. ⚠️ NOTICE ⚠️: moved to the PouchDB repo

436 Stars 77 Forks Last release: Not found Apache License 2.0 208 Commits 19 Releases

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⚠️ NOTE ⚠️: this project has moved to the PouchDB GitHub repo. Please submit new issues/PRs there!

The

pouchdb-find
plugin is being incorporated into PouchDB itself. Original documentation follows:

PouchDB Find Build Status Coverage Status

(Live demo)

Provides a simple, MongoDB-inspired query language that accomplishes the same thing as the map/reduce API, but with far less code.

Eventually this will replace PouchDB's map/reduce API entirely. You'll still be able to use map/reduce, but it will be distributed as a separate plugin.

Status

Implemented:

$lt
,
$gt
,
$lte
,
$gte
,
$eq
,
$exists
,
$type
,
$in
,
$nin
,
$all
,
$size
,
$or
,
$nor
,
$not
,
$mod
,
$regex
,
$elemMatch
, multi-field queries, multi-field indexes, multi-field sort,
'deep.fields.like.this'
, ascending and descending sort.

0.2.0:

$and
,
$ne

0.3.0:

limit
,
skip
,
ddoc
when creating an index

0.4.0:

total_rows

0.5.0:

$in
,
$nin
,
$all
,
$size

0.6.0:

$or
,
$nor
,
$not

0.7.0:

$elemMatch
,
$regex

0.8.0: Bug fixes for $and, $type, $exists

0.9.0: Bug fixes for

$elemMatch
. Rewrite of in-memory operator

0.10.0: Update for latest Mango spec (warnings instead of errors), update for PouchDB 5.4.0.

Usage

In the browser

To use this plugin in the browser, include it after

pouchdb.js
in your HTML page:

You can also download it from Bower:

bower install pouchdb-find

In Node.js/Browserify

Or to use it in Node.js, just npm install it:

npm install pouchdb-find

And then attach it to the

PouchDB
object:
var PouchDB = require('pouchdb');
PouchDB.plugin(require('pouchdb-find'));

API

This API is modeled after the Cloudant query API, merged into CouchDB 2.0. Read that page for more details.

As with PouchDB, the entire API accepts either the callback or the Promise style.

Overview

db.createIndex(index [, callback])

Create an index if it doesn't exist, or do nothing if it already exists.

Example:

db.createIndex({
  index: {
    fields: ['foo']
  }
}).then(function (result) {
  // yo, a result
}).catch(function (err) {
  // ouch, an error
});

The result can be either:

{"result": "created"} // index was created

or:

{"result": "exists"} // index already exists

You can also create an index on multiple fields:

db.createIndex({
  index: {
    fields: ['foo', 'bar', 'baz']
  }
});

Or an index on deep fields:

db.createIndex({
  index: {
    fields: ['person.address.zipcode']
  }
});

You can also specify additional options, if you want more control over how your index is created:

db.createIndex({
  index: {
    fields: ['foo', 'bar'],
    name: 'myindex',
    ddoc: 'mydesigndoc'
    type: 'json',
  }
});

Options

  • fields
    is a list of fields to index
  • name
    (optional) name of the index, auto-generated if you don't include it
  • ddoc
    (optional) design document name (i.e. the part after
    '_design/'
    , auto-generated if you don't include it
  • type
    (optional) only supports
    'json'
    , and it's also the default

db.getIndexes([callback])

Get a list of all the indexes you've created. Also tells you about the special

_all_docs
index, i.e. the default index on the
_id
field.

Example:

db.getIndexes().then(function (result) {
  // yo, a result
}).catch(function (err) {
  // ouch, an error
});

Example result:

{
  "indexes": [
    {
      "ddoc": null,
      "name": "_all_docs",
      "type": "special",
      "def": {
        "fields": [
          {
            "_id": "asc"
          }
        ]
      }
    },
    {
      "ddoc": "_design/idx-0f3a6f73110868266fa5c688caf8acd3",
      "name": "idx-0f3a6f73110868266fa5c688caf8acd3",
      "type": "json",
      "def": {
        "fields": [
          {
            "foo": "asc"
          },
          {
            "bar": "asc"
          }
        ]
      }
    }
  ]
}

db.deleteIndex(index [, callback])

Delete an index and clean up any leftover data on the disk.

Options

  • index
    Definition of an index to delete. You can pass it in exactly as you received it from the
    getIndexes()
    API. You cannot delete the built-in
    _all_docs
    index.

Example:

db.deleteIndex({
  "ddoc": "_design/idx-0f3a6f73110868266fa5c688caf8acd3",
  "name": "idx-0f3a6f73110868266fa5c688caf8acd3",
  "type": "json",
  "def": {
    "fields": [
      {
        "foo": "asc"
      },
      {
        "bar": "asc"
      }
    ]
  }
}).then(function (result) {
  // yo, a result
}).catch(function (err) {
  // ouch, an error
});

Notice that you don't need to provide a

_rev
! The design doc is also deleted.

db.find(request [, callback])

Query the API to find some documents.

Example:

db.find({
  selector: {name: 'Mario'},
  fields: ['_id', 'name'],
  sort: ['name']
}).then(function (result) {
  // yo, a result
}).catch(function (err) {
  // ouch, an error
});

Example result:

{
  "docs": [
    {
      "_id": "mario",
      "name": "Mario"
    }
  ]
}

Options;

  • selector
    Defines a selector to filter the results. Required.
    • $lt
      Match fields "less than" this one.
    • $gt
      Match fields "greater than" this one.
    • $lte
      Match fields "less than or equal to" this one.
    • $gte
      Match fields "greater than or equal to" this one.
    • $eq
      Match fields equal to this one.
    • $ne
      Match fields not equal to this one.
    • $exists
      True if the field should exist, false otherwise.
    • $type
      One of: "null", "boolean", "number", "string", "array", or "object".
    • $in
      Matches if all the selectors in the array match.
    • $and
      Matches if all the selectors in the array match.
    • $nin
      The document field must not exist in the list provided.
    • $all
      Matches an array value if it contains all the elements of the argument array.
    • $size
      Special condition to match the length of an array field in a document.
    • $or
      Matches if any of the selectors in the array match. All selectors must use the same index.
    • $nor
      Matches if none of the selectors in the array match.
    • $not
      Matches if the given selector does not match.
    • $mod
      Matches documents where (field % Divisor == Remainder) is true, and only when the document field is an integer.
    • $regex
      A regular expression pattern to match against the document field.
    • $elemMatch
      Matches all documents that contain an array field with at least one element that matches all the specified query criteria.
  • fields
    (Optional) Defines a list of fields that you want to receive. If omitted, you get the full documents.
  • sort
    (Optional) Defines a list of fields defining how you want to sort. Note that sorted fields also have to be selected in the
    selector
    .
  • limit
    (Optional) Maximum number of documents to return.
  • skip
    (Optional) Number of docs to skip before returning.

If there's no index that matches your

selector
/
sort
, then this method will issue a warning.

The best index will be chosen automatically. If you want to see the query plan for your query, then turn on debugging.

See the Cloudant docs for more details.

Examples

Equals

Find all docs where

doc.name === 'Mario'
:
db.find({
  selector: {name: {$eq: 'Mario'}}
});

This is equivalent to:

db.find({
  selector: {name: 'Mario'}
});

Multi-selectors

Find all docs where

doc.series === 'Mario'
and
doc.debut > 1990
:
db.find({
  selector: {
    series: 'Mario',
    debut: { $gt: 1990 }
  }
});

This is equivalent to:

db.find({
  selector: {
    $and: [
      { series: 'Mario' },
      { debut: { $gt: 1990 } }
    ]
  }
});

Sorting

Return all docs sorted by

doc.debut
descending:
db.find({
  selector: {
    debut: {'$exists': true}
  },
  sort: [{debut: 'desc'}]
});

For more examples, refer to Cloudant's

_find
documentation.

With a remote database

Over HTTP, this plugin currently works with Cloudant and CouchDB 2.0. Cloudant is the reference implementation, so the API should be the same.

PouchDB Server also has this API, since it includes this very plugin by default.

Debugging

Just call:

PouchDB.debug.enable('pouchdb:find')

Then

pouchdb-find
will start logging some debug information to the console. This can be useful if, for instance, you want to see the query plan that is being used to execute your queries.

Kudos

Thanks very much to @garrensmith for implementing all the new features from 0.4.0 to 0.6.0!

How to contribute to this thing

Instructions are in CONTRIBUTING.md.

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