pouchdb-find
v9.0.0
Published
Easy-to-use query language for PouchDB
Downloads
157,334
Readme
PouchDB Find
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.
Warning: this is beta software! It may change at anytime and could be unstable.
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, partial indexes.
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:
<script src="pouchdb.js"></script>
<script src="pouchdb.find.js"></script>
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])
db.getIndexes([callback])
db.deleteIndex(index [, callback])
db.find(request [, callback])
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 indexname
(optional) name of the index, auto-generated if you don't include itddoc
(optional) design document name (i.e. the part after'_design/'
, auto-generated if you don't include ittype
(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 thegetIndexes()
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 theselector
.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.