Reactive Extensions Helpers

Helper functions for the Reactive Extensions for JavaScript

Documentation

• Rx.helpers.defaultComparer
• Rx.helpers.defaultSubComparer
• Rx.helpers.defaultError
• Rx.helpers.identity
• Rx.helpers.isPromise
• Rx.helpers.noop

Rx.helpers.defaultComparer(x, y)

#Ⓢ [Ⓣ][1]

The default equality comparer, used when a comparer is not supplied to a function. Uses an internal deep equality check.

Arguments

1. x (Any): The first value to compare
2. y (Any): The second value to compare

Returns

(Boolean): true if equal; else false.

Example

var comparer = Rx.helpers.defaultComparer;

// Should return true
var x = 42, y = 42
console.log(comparer(x, y));
// => true

// Should return false
var x = new Date(0), y = new Date();
console.log(comparer(x, y));
// => false

Rx.helpers.defaultSubcomparer(x, y)

#Ⓢ [Ⓣ][1]

The default comparer to determine whether one object is greater, less than or equal to another.

Arguments

1. x (Any): The first value to compare
2. y (Any): The second value to compare

Returns

(Number): Returns 1 if x is greater than y, -1 if y is greater than x, and 0 if the objects are equal.

Example

var comparer = Rx.helpers.defaultSubcomparer;

// Should return 0
var x = 42, y = 42
console.log(comparer(x, y));
// => 0

// Should return -1
var x = new Date(0), y = new Date();
console.log(comparer(x, y));
// => -1

// Should return 1
var x = 43, y = 42;
console.log(comparer(x, y));
// => 1

Rx.helpers.defaultError(err)

#Ⓢ [Ⓣ][1]

Throws the specified error

Arguments

1. err (Any): The error to throw

Example

var defaultError = Rx.helpers.defaultError;

// Returns its value
defaultError(new Error('woops'))
// => Error: woops

Rx.helpers.identity(x)

#Ⓢ [Ⓣ][1]

A function which returns its value unmodified.

Arguments

1. x (Any): The value to return.

Returns

(Any): The value given as the parameter.

Example

var identity = Rx.helpers.identity;

// Returns its value
var x = identity(42);
console.log(x);
// => 42

Rx.helpers.isPromise(p)

#Ⓢ [Ⓣ][1]

A function which determines whether the object is a Promise.

Arguments

1. p (Any): The object to determine whether it is a promise.

Returns

(Boolean): true if the object is a Promise else false

Example

var isPromise = Rx.helpers.isPromise;

var p = RSVP.Promise(function (res) { res(42); });

console.log(isPromise(p));
// => true

Rx.helpers.noop()

#Ⓢ [Ⓣ][1]

A function which does nothing

Example

var noop = Rx.helpers.noop;

// This does nothing!
noop();