Bacon.matchers NPM

Matcher library for Bacon.js.

You can map a Property / EventStream to a boolean one like using .is()

// Returns a Property of Booleans
age.is().equalTo(65)
salary.is().greaterThan(1000)

You can also filter using .where()

// Returns a filtered stream
keyUps.map(".keyCode").where().equalTo(30)

And there's negation

age.is().not().greaterThan(18)

You can compare to either constant values or other Observables. Like

// Returns a Property of Booleans
var collision = playerPos.is().equalTo(monsterPos)

You can give field extractor strings to .where() and .is(), like this:

Bacon.fromArray([
	{ name: "2001: A Space Odyssey", tags: ["SciFi"] },
	{ name: "The Godfather", tags: ["Crime", "Drama"] },
]).where('.tags').containerOf("SciFi")

=> { name: "2001: A Space Odyssey", tags: ["SciFi"] }

Bacon.fromArray([
	{ name: "2001: A Space Odyssey", tags: ["SciFi"] },
	{ name: "The Godfather", tags: ["Crime", "Drama"] },
]).is('.tags.length').greaterThan(1)

=> false, true

Complete examples:

Bacon.fromArray([1,2,3]).is().equalTo(2)

=> false, true, false

Bacon.fromArray([1,2,3]).where().equalTo(2)

=> 2

Additions to Observable API

Observable.is() returns a Matchers object for mapping to booleans.

Observable.where() returns a Matchers object for filtering.

Matchers API

lessThan(x) applies < matcher

lessThanOrEqualTo(x) applies <= matcher

greaterThan(x) applies > matcher

greaterThanOrEqualTo applies >= matcher

inClosedRange(a, b) applies [a..b] range matcher

inOpenRange(a, b) applies (a..b) range matcher

equalTo(x) applies == matcher

truthy() applies "truthy" matcher

match(expr) applies regular expression matcher

not() returns a negated Matchers object

containerOf(x) and memberOf(x) support arrays, strings and object key-values. Examples:

stream = Bacon.once([6]).is().containerOf(6) // is true
stream = Bacon.once(6).is().memberOf([6]) // is true

Bacon.once('hello bacon').is().containerOf('bacon') // is true
Bacon.once('bacon').is().memberOf('hello bacon') // is true

Bacon.once({
  alien: 'morninglightmountain'
  human: 'dudleybose'
}).is().containerOf({ alien: 'morninglightmountain' }) // is true

Bacon.once({ alien: 'morninglightmountain' })
  .is().memberOf({
  alien: 'morninglightmountain'
  human: 'dudleybose'
}) // is true

some(fs...) applies multiple "clauses", and matches when any clause is true. Clauses are functions that map the observable to an observable of boolean values. For example:

Bacon.once({ power_pill: true,   ghosts: ["Inky", "Pinky"]})
  .is()
  .some(
    function(stream){ return stream.is(".power_pill").truthy(); },
    function(stream){ return stream.is(".ghosts").containerOf("Clyde"); }
  ) // is true

every(fs...) applies multiple "clauses", and matches when all clauses are true. For example:

Bacon.once({ power_pill: true,   ghosts: ["Inky", "Pinky"]})
  .is()
  .every(
    function(stream){ return stream.is(".power_pill").truthy(); },
    function(stream){ return stream.is(".ghosts").containerOf("Clyde"); }
  ) // is false