AprilArcus

// Recipe for a pedantically correct subclass of JavaScript's built-in
// "Error" constructor.
//   * Preserves the ability of JS Errors to be constructed with
//     a `new`-less function call
//   * Can be subclassed itself
//   * Backward- and Forward-compatible TypeScript annotations
//   * Correct enumerable / writable / configurable settings on
//     .prototype, .prototype.constructor, .prototype.name, and
//     custom instance fields.

AprilArcus

/* @flow */

export function foo(test: boolean, callback: () => Array<number>): Array<number|string> {
  if (test) return [1, '1'];
  return callback();
}

  3: export function foo(test: boolean, callback: () => Array<number>): Array<number|string> {
                                                                                     ^^^^^^ string. This type is incompatible with
  3: export function foo(test: boolean, callback: () => Array<number>): Array<number|string> {

AprilArcus

$ flow check

src/injectCallbacks.js:0
  0:
     ^ inconsistent use of library definitions
 67:     detachEvent?: (type: string, listener: EventListener) => void;
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ undefined. This type is incompatible with. See: /private/tmp/flow/flowlib_2dc60f56/dom.js:67
 67:     detachEvent?: (type: string, listener: EventListener) => void;
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function type. See: /private/tmp/flow/flowlib_2dc60f56/dom.js:67

AprilArcus

/* @flow */

declare class SVGElement extends Element {}

declare class HTMLParagraphElement extends HTMLElement {
  align: string;
}

type ElementRegistrationOptions<T> = {
  prototype?: {

AprilArcus

element.js:

------------------------------
/* @flow */
declare class HTMLParagraphElement extends HTMLElement {
  align: string
}

type CustomElementCallbacks = {
  createdCallback?: () => void;

AprilArcus

element.js

/* @flow */
declare class HTMLParagraphElement extends HTMLElement {
  align: string
}

declare class Document extends Node {
  registerElement(type: string, options?: ElementRegistrationOptions): void;
}

AprilArcus

import { default as React, Component, Children, cloneElement } from 'react';

class ComponentWithComputedWidths extends Component {
  constructor(props) {
    super(props);
    this.state = { computedWidthsAvailable = false; computedWidths: {} };
    this.updateComputedWidths = this.updateComputedWidths.bind(this);
  }

  updateComputedWidths() {

AprilArcus

<!-- polyfills -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/bluebird/2.9.34/bluebird.min.js">
<script src="https://cdnjs.cloudflare.com/ajax/libs/fetch/0.9.0/fetch.min.js">

<script>

var imageCache = {};
function preload(name) {
  var url = "images/" + name + ".jpg";
  return fetch(url) // returns a promise...

AprilArcus

export default React.createClass({

    displayName: 'Oceans Navigation Category',

    propTypes: {
        list: React.PropTypes.arrayOf(
            React.PropTypes.shape({
                humanReadableName: React.PropTypes.string,
                url: React.PropTypes.string
            })

AprilArcus

// bootstrap React Router
import React from 'react';
import { default as Router, Route, DefaultRoute, HistoryLocation, RouteHandler } from 'react-router';
import { Splash } from '../components_angular/splash';

import index from './index';
let oceans;
if (!PRODUCTION) {
    oceans = (
        <Route handler={require('./oceans/navigation')} path='oceans'>