ohanhi

Learning FP the hard way: Experiences on the Elm language

by Ossi Hanhinen, @ohanhi

with the support of Futurice 💚.

Licensed under CC BY 4.0.

Editorial note

threepointone

import React from 'react';

export class Sto extends React.Component{
  static defaultProps = {
    store: x => x
  }
  state = {
    value: this.props.store()
  }
  dispatch = action => this.setState({

axefrog

'use strict';

import {Router5, RouteNode} from 'router5';
import logger from '../logger';

// The set of valid sink functions includes synchronous state-affecting router functions that do not require a callback
// and which do not have a significant return value other than the router object itself.
const validSinkFuncs = ['add','addNode','canActivate','deregisterComponent','navigate','registerComponent','setOption','start','stop'];

function validateAndRemapSinkArgument(arg) {

axefrog

function runInScope(main, sources, context, ...args) {
  if(!main) {
    throw new Error('A "main" function must be supplied, which will be called in scope and from which a (sinks) object will be returned');
  }
  if(!sources) {
    throw new Error('A source drivers object must be supplied, to which scoping can be applied');
  }
  if(!context) {
    throw new Error('A scope context object must be supplied, either as a string, or as an object of key/value pairs');
  }

kpuputti

/*eslint-env es6 */

// Inspired by the paper "A tutorial on the universality and
// expressiveness of fold" by Graham Hutton (available at
// http://www.cs.nott.ac.uk/~gmh/fold.pdf), implementing some generic
// list handling functions in JavaScript in terms of `fold`.

// Personally I had an enlightnening moment when I realised the
// beautiful interplay of cons lists and foldr during the FP101x
// Haskell course. JavaScript's syntax doesn't make this very apparent

teropa

In my proposed lightning talk for the Reactive Conference, I'll create Conway's Game of Life in ClojureScript, and I'll do it in five minutes. I'll use an interactive programming workflow enabled by Figwheel. Each piece will be added into the running application without reloading the page.

If you want to see a little cellular lifeform spawn out of nothing into an running web browser window, I'd appreciate it if you starred this Gist!

Cheers,

(@teropa)

ohanhi

This is a proposal for a lightning talk at the Reactive 2015 conference.

NOTE: If you like this, star ⭐ the Gist - the amount of stars decides whether it makes the cut!

The Joy of Composition

Why stateless rendering is pure bliss

React just got stateless components, meaning that they are in essence pure functions for rendering. Pure functions make it dead simple - even fun - to refactor your views

antonycourtney

A realistic RxJS app with diamond wiring

Consider the following user interface (inspired by Strava) for looking at time-series charts of network data:

Notes on this interface and my Rx implementation of it:

• Each chart (stacked vertically) charts a different metric (latency, packet loss and throughput) but over the same time period.
• As the user moves the mouse left and right on any chart, the vertical line (called the tracker) moves to track the mouse position on all charts. The number displayed in the gray box on the right is the value underneath the tracker for that metric.

zudov

Cycle.js approach to handling IO looks similar to how it was done in earlier FRP implementations. That seems to be an independent discovery, and that's always even better.

Yampa provides a function reactimate:

:: IO a	-- ^ IO initialization action
-> (Bool -> IO (DTime, Maybe a)) -- ^ IO input sensing action
-> (Bool -> b -> IO Bool)        -- ^ IO actuaction (output processing) action
-> SF a b	-- ^ Signal function

tomkis

import { createStore, applyMiddleware } from 'redux';
import { Observable, Subject } from 'rxjs';

const api = type => {
  console.log(`calling API ${type}`);
  return new Promise(res => setTimeout(() => res(), 500));
};

const actionOrder = (actions, order) => actions.every((action, index) => action.type === order[index]);
const actionPredicate = actions => filterableAction => actions.some(action => action === filterableAction.type);