A lightweight (3KB minified) utility for Backbone projects, that works in the Browser and on the Server. Adds the ability to search for models with a Query API similar to MongoDB Please report any bugs, feature requests in the issue tracker. Pull requests are welcome!
Client Side Installation:
To install, include the
js/backbone-query.min.js file in your HTML page, after Backbone and it's dependencies.
Then extend your collections from Backbone.QueryCollection rather than from Backbone.Collection.
Server side (node.js) installation
You can install with NPM:
npm install backbone-query
Then simply require in your project:
QueryCollection = require("backbone-query").QueryCollection
Your collections will now have two new methods:
where. Both methods accept 2 arguments -
a query object and an options object. The
query method returns an array of models, but the
returns a new collection and is therefore useful where you would like to chain multiple collection
methods / where queries. The following are some basic examples:
MyCollection;// Returns all models where the featured attribute is true and there are// more than 10 likesMyCollection;// Finds models that have either "coffeescript", "backbone", "mvc" in their "tags" attribute// Sorts these models by the "likes" attribute in descending order// Caches the results and returns only 10 models, starting from the 11th model (page 2)MyCollection;
Or if CoffeeScript is your thing (the source is written in CoffeeScript), try this:
MyCollectionquery$and:likes: $lt: 15$or:content: $like: "news"featured: $exists: true$not:colors: $contains: "yellow"
Another CoffeeScript example, this time using
where rather than
query =$likes: $lt: 10$downloads: $gt: 20MyCollectionwherequerymy_custom_collection_method
Performs a strict equality test using
===. If no operator is provided and the query value isn't a regex then
$equal is assumed.
MyCollection;// Returns all models which have a "title" attribute of "Test"MyCollection; // Same as above
Assumes that the model property is an array and searches for the query value in the array
MyCollection;// Returns models which contain the value "red" in a "colors" attribute that is an array.// e.g. a model with this attribute colors:["red","yellow","blue"] would be returned
"Not equal", the opposite of $equal, returns all models which don't have the query value
MyCollection;// Returns all models which don't have a "title" attribute of "Test"
$lt, $lte, $gt, $gte
These conditional operators can be used for greater than and less than comparisons in queries
MyCollection;// Returns all models which have a "likes" attribute of less than 10MyCollection;// Returns all models which have a "likes" attribute of less than or equal to 10MyCollection;// Returns all models which have a "likes" attribute of greater than 10MyCollection;// Returns all models which have a "likes" attribute of greater than or equal to 10
To check if a value is in-between 2 query values use the $between operator and supply an array with the min and max value
MyCollection;// Returns all models which have a "likes" attribute of greater than 5 and less then 15
An array of possible values can be supplied using $in, a model will be returned if any of the supplied values is matched
MyCollection;// Returns all models which have a title attribute of either "About", "Home", or "Contact"
"Not in", the opposite of $in. A model will be returned if none of the supplied values is matched
MyCollection;// Returns all models which don't have a title attribute of either// "About", "Home", or "Contact"
Assumes the model property is an array and only returns models where all supplied values are matched.
MyCollection;// Returns all models which have "red" and "yellow" in their colors attribute.// A model with the attribute colors:["red","yellow","blue"] would be returned// But a model with the attribute colors:["red","blue"] would not be returned
Assumes the model property is an array and returns models where any of the supplied values are matched.
MyCollection;// Returns models which have either "red" or "yellow" in their colors attribute.
Assumes the model property has a length (i.e. is either an array or a string). Only returns models the model property's length matches the supplied values
MyCollection;// Returns all models which 2 values in the colors attribute
$exists or $has
Checks for the existence of an attribute. Can be supplied either true or false.
MyCollection;// Returns all models which have a "title" attributeMyCollection;// Returns all models which don't have a "title" attribute
Assumes the model attribute is a string and checks if the supplied query value is a substring of the property. Uses indexOf rather than regex for performance reasons
MyCollection;//Returns all models which have a "title" attribute that//contains the string "Test", e.g. "Testing", "Tests", "Test", etc.
The same as above but performs a case insensitive search using indexOf and toLowerCase (still faster than Regex)
MyCollection;//Returns all models which have a "title" attribute that//contains the string "Test", "test", "tEst","tesT", etc.
Checks if the model attribute matches the supplied regular expression. The regex query can be supplied without the
MyCollection;// Checks for a regex match in the content attributeMyCollection;// Same as above
A callback function can be supplied as a test. The callback will receive the attribute and should return either true or false.
this will be set to the current model, this can help with tests against computed properties
MyCollection;// Returns all models that have a title attribute that starts with "c"MyCollection;// Returns all models where the computed_property method returns a value greater than 10.
For callbacks that use
this rather than the model attribute, the key name supplied is arbitrary and has no
effect on the results. If the only test you were performing was like the above test it would make more sense
to simply use
MyCollection.filter. However if you are performing other tests or are using the paging / sorting /
caching options of backbone query, then this functionality is useful.
Multiple queries can be combined together. By default all supplied queries must be matched
$and. However it is possible
to specify either
$not to implement alternate logic.
MyCollection;// Returns all models that contain "News" in the title and have more than 10 likes.MyCollection;// Same as above as $and is assumed if not supplied
MyCollection;// Returns all models that contain "News" in the title OR have more than 10 likes.
The opposite of
MyCollection;// Returns all models that don't contain "News" in the title NOR have more than 10 likes.
The opposite of
MyCollection;// Returns all models that don't contain "News" in the title AND DON'T have more than 10 likes.
It is possible to use multiple combined queries, for example searching for models that have a specific title attribute, and either a category of "abc" or a tag of "xyz"
MyCollection;//Returns models that have "News" in their title and//either have more than 10 likes or contain the color red.
order attributes can be supplied as part of an options object.
sortBy can either be a model key or a callback function which will be called with each model in the array.
MyCollection;// Returns all models that contain "News" in the title,// sorted according to their "likes" attribute (ascending)MyCollection;// Same as above, but "descending"MyCollection;// Results sorted according to 2nd character of the title attribute
To return only a subset of the results paging properties can be supplied as part of an options object.
limit property must be supplied and optionally a
offset or a
page property can be supplied.
MyCollection;// Returns the first 10 models that have more than 10 likesMyCollection;// Returns 10 models that have more than 10 likes starting//at the 6th model in the resultsMyCollection;// Returns 10 models that have more than 10 likes starting//at the 11th model in the results (page 2)
When using the paging functionality, you will normally need to know the number of pages so that you can render
the correct interface for the user. Backbone Query can send the number of pages of results to a supplied callback.
The callback should be passed as a
pager property on the options object. This callback will also receive the sliced
models as a second variable.
Here is a coffeescript example of a simple paging setup using the pager callback option:
To enable caching set the cache flag to true in the options object. This can greatly improve performance when paging
through results as the unpaged results will be saved. This options is not enabled by default as if models are changed,
added to, or removed from the collection, then the query cache will be out of date. If you know
that your data is static and won't change then caching can be enabled without any problems.
If your data is dynamic (as in most Backbone Apps) then a helper cache reset method is provided:
reset_query_cache. This method should be bound to your collections change, add and remove events
(depending on how your data can be changed).
Cache will be saved in a
_query_cache property on each collection where a cache query is performed.
MyCollection;//The first query will operate as normal and return the first page of resultsMyCollection;//The second query has an identical query object to the first query, so therefore the results will be retrieved//from the cache, before the paging paramaters are applied.// Binding the reset_query_cache methodvar MyCollection = BackboneQueryCollection;
Dave Tonge - davidgtonge