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    2.1.0 • Public • Published


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    A utility wrapper for set operations using arrays of objects. Work with sets as if they were simple arrays! Updated for ES6 proxies( For Harmony Proxies, please use <= 1.x).

    Each set has a chain of ancestry which, at it's root, is a collection. All values are held in the collections, while the sets themselves are simply orderings across subsets of ids


    First, require the module:

    var Indexed = require('indexed-set');

    Then create a collection:

    var collection = new Indexed.Collection(<array>, [<keyName>]);

    where keyName defaults to Mongo's '_id' or

    var collection = new Indexed.Collection(<options>);

    The available options are:

    1. datasource : the mongo adapter
    2. name : the name of the collection to load
    3. onLoad : executed when the collection load is complete

    then to create a set:

    new Indexed.Set(collection);

    If I want to initialize the set from a mongo collection using the built-in mongo adapter it would look like this:

    var MongoAdapter = require('indexed-set/mongo');
    var collection = new Indexed.Collection({
        name : 'my_awesome_collection',
        datasource : new MongoAdapter(options.database);,
        onLoad: function(){
            var mySet = new Indexed.Set(collection);
            //do stuff here

    Internal Data Access

    1. getByPosition(position) : retrieve the object by the position of the object within the set
    2. getById(id) : retrieve the object by it's primary key within the set
    3. setByIdFromString(id, idString) : substitue the object with id idString for the position of the passed id
    4. setByPositionFromString(position, idString) : substitue the object with id idString for the passed position
    5. setByIdFromObject(id, object) : substitue this object at the position of the object with the passed in id
    6. setByPositionFromObject(position, object) : substitue this object at the position provided

    additionally you are able to call:


    which wraps a proxy around the object so you can use an array-like syntax:

    so given a set:

    var collection = new Indexed.Collection([
    ], 'a');
    var mySet = new Indexed.Set(collection);

    I could say:


    which resolves to:


    as does[0]

    and, as another example:




    Meaning you can either address by primary key or position.

    Array Syntax

    The Set class implements a number of the standard array methods, for familiarity

    1. indexOf(object)
    2. forEach(iteratorFunction)
    3. push(object)
    4. pop()
    5. shift()
    6. slice(start, [stop]) : take a subset by index range

    Set Functions

    This is the meat of the library allowing you to manipulate and analyze datasets while still staying economical with memory and performance.

    1. and(set) : the union of all objects in both sets
    2. or(set) : all objects in either set
    3. xor(set) : all objects contained in one set, but not both
    4. not(set) : all objects not present in 'set'
    5. filter(filterFunction) : a filter passed across the set to determine if a given element is selected or not
    6. with(field, comparison, value) : a convenience method to generate a filter
    7. byGroup(field) : segment along a given field and bin objects by the value on that field. returns an object of arrays
    8. distinct([field]) : return all potential values for a given field, or if none is provided, provide all options for all fields, broken down by field.
    9. clone() : make a copy of the set (this is a relatively cheap operation, in comparison to many clone() functions)
    10. resume() : allow filters to execute as they are applied (started by default), also executes queued filters
    11. pause() : queue applied filters instead of immediately executing them.
    12. filterFunction() : return a function which is a composite of all filter functions on this set(can be passed to mongo as a selector function).
    13. hierarchy(hierarchies, [fields]) : the tree of dependencies by node based on the descending relationships (provided an array of arrays of fieldNames). This produces overlapping relationship trees based on the passed priority. I won't go into further detail because this is a CPU bound task. If you don't know how to compensate for that, avoid the feature, lest you have unresponsive services.
    14. aggregate(field, [aggregatorFn]) : aggregate all set members on a given field, default aggregation is just a = a + b.


    Run the test harness at the project root with:



    -Abbey Hawk Sparrow


    npm i indexed-set

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