Class: Dommy::PromiseValue

Inherits:
Object
  • Object
show all
Includes:
Bridge::Methods
Defined in:
lib/dommy/promise.rb

Overview

Note: PromiseConstructor and PromiseSettler live in Dommy::Bridge::* — they're bridge-adapter classes for the JS.global[:Promise] view, not part of the public DOM surface.

Defined Under Namespace

Classes: Handler

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Bridge::Methods

included

Constructor Details

#initialize(window) ⇒ PromiseValue

Returns a new instance of PromiseValue.



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# File 'lib/dommy/promise.rb', line 47

def initialize(window)
  @window = window
  @state = :pending
  @value = nil
  @handlers = []
end

Class Method Details

.reject(window, reason) ⇒ Object 



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# File 'lib/dommy/promise.rb', line 41

def self.reject(window, reason)
  promise = new(window)
  promise.reject(reason)
  promise
end

.resolve(window, value) ⇒ Object 



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# File 'lib/dommy/promise.rb', line 35

def self.resolve(window, value)
  promise = new(window)
  promise.fulfill(value)
  promise
end

Instance Method Details

#__js_call__(method, args) ⇒ Object 



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# File 'lib/dommy/promise.rb', line 56

def __js_call__(method, args)
  case method
  when "then"
    attach_then(args[0], args[1])
  when "catch"
    attach_then(nil, args[0])
  when "finally"
    attach_finally(args[0])
  else
    nil
  end
end

#await ⇒ Object

Synchronously unwrap the promise's settled value, or raise its rejection. Dommy's scheduler is deterministic, so "wait" is spelled "drain queued microtasks then read the state."

This is the bridge between dommy's async APIs (fetch, etc.) and Ruby tests that want to write straight-line code:

response = win.__js_call__("fetch", [url]).await
text     = response.text

Raises RuntimeError if the promise is still pending after a microtask drain — that's a sign that real-time work (e.g. a setTimeout) needs to advance via advance_time first.



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# File 'lib/dommy/promise.rb', line 90

def await
  drive_until_settled

  case @state
  when :fulfilled
    @value
  when :rejected
    raise unwrap_rejection(@value)
  else
    raise "Promise#await: still pending after draining the event loop"
  end
end

#fulfill(value) ⇒ Object 



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# File 'lib/dommy/promise.rb', line 69

def fulfill(value)
  settle(:fulfilled, value)
end

#reject(reason) ⇒ Object 



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# File 'lib/dommy/promise.rb', line 73

def reject(reason)
  settle(:rejected, reason)
end