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Selection ​

A Selection is a specialized Param that manages a collection of Boolean-valued predicates that can be used to interactively filter a data source.

Selections apply a resolution strategy to merge clauses into client-specific predicates:

  • The single strategy simply includes only the most recent clause.
  • The union strategy performs disjunction, combining all predicates via Boolean OR.
  • The intersect strategy performs conjunction via Boolean AND.

In addition, selections can be cross-filtered, so that they affect views other than the one currently being interacted with. The strategies above are modified to omit clauses where the clients set includes the input argument to the predicate() function.

isSelection ​

isSelection(value)

Returns true if the input value is a Selection, false otherwise.

Selection.intersect ​

Selection.intersect(options)

Create a new Selection instance with an intersect (conjunction) resolution strategy.

The options object may include a Boolean cross flag (default false) indicating cross-filtered resolution. If true, selection clauses will not be applied to the clients they are associated with.

Selection.union ​

Selection.union(options)

Create a new Selection instance with a union (disjunction) resolution strategy.

The options object may include a Boolean cross flag (default false) indicating cross-filtered resolution. If true, selection clauses will not be applied to the clients they are associated with.

Selection.single ​

Selection.single(options)

Create a new Selection instance with a singular resolution strategy that keeps only the most recent selection clause.

The options object may include a Boolean cross flag (default false) indicating cross-filtered resolution. If true, selection clauses will not be applied to the clients they are associated with.

Selection.crossfilter ​

Selection.crossfilter()

Create a new Selection instance with a cross-filtered intersect resolution strategy. This is a convenience method for Selection.intersect({ cross: true }).

clone ​

selection.clone()

Create a cloned copy of this Selection instance.

remove ​

selection.remove(source)

Create a clone of this Selection with clauses corresponding to the provided source removed.

active ​

selection.active

Property getter for the current active (most recently updated) selection clause.

value ​

selection.value

The value corresponding to the current active selection clause. Selections override the Param.value property to return the active clause value, making selections compatible where standard params are expected.

clauses ​

selection.clauses

The current array of selection clauses.

activate ​

selection.activate(clause)

Emit an activate event with the given selection clause.

These activate events provide a clause indicative of likely future updates. For example, a brush interactor may trigger an activation event when the cursor enters a brushable region, providing an example clause prior to any actual updates. Activation events can be used to implement optimizations such as prefetching.

update ​

selection.update(clause)

Update the selection with a new selection clause. A clause is an object consisting of:

  • the source component (such as a client or interactor) providing the clause,
  • a set of clients associated with the clause, indicating the clients that should be skipped in the case of cross-filtering,
  • a query predicate (e.g, the range predicate column BETWEEN 0 AND 1),
  • a corresponding value (e.g., the range array [0,1]), and
  • an optional schema providing clause metadata.

Upon update, any prior clause with the same source is removed and the new, most recent clause (called the active clause) is added.

predicate ​

selection.predicate(client)

Return a selection query predicate for the given Mosaic client. The resulting predicate can be used as part of a SQL WHERE clause.

addEventListener ​

selection.addEventListener(type, callback)

Add an event listener callback function for the specified event type. Selections support both "value" and "activate" type events.

removeEventListener ​

selection.removeEventListener(type, callback)

Remove an event listener callback function for the specified event type.