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const lastIndex = list => (
  list && list.length > 0 ? list.length - 1 : 0);

const isNone = val => val === null || typeof val === 'undefined';

const asList = list => (isNone(list) ? [] : list);

const isEmptyList = list => list && list.length <= 0;

const isLastIndex = (lst, index) => (asList(lst).length - 1) === index;

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const bt = (value, left, right) => {
  return {
    value: value,
    left: left,
    right: right
  };
}

const leaf = value => {
  return bt(value, null, null);

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<script>
function execPolyfill() {

(function(){
// CustomElementsV1.min.js v1 polyfill from https://github.com/webcomponents/webcomponentsjs/tree/v1/src/CustomElements/v1.
/*
 Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt

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package recfun

object Main {
  def main(args: Array[String]) {
    println("Pascal's Triangle")
    for (row <- 0 to 10) {
      for (col <- 0 to row)
        print(pascal(col, row) + " ")
      println()
    }

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// If you use Redux Thunk...
import { createStore, applyMiddleware } from 'redux'
import thunk from 'redux-thunk'
const store = createStore(reducer, applyMiddleware(thunk))

// You can define asynchronous action creators that return functions.
// We call such action creators "thunks":

export function getUser(id) {
  // Redux Thunk will inject dispatch here:

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Pattern Matching

Example

type basicColor =
	| Red
	| Green
	| Blue;

let basicColorToInt = color => {

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const R = require('ramda');
const { append, compose, filter, flatten, isArray, join, map, prepend } = R
const { log } = console

// html markup functions
const UL = 'ul'

const LI = 'li'

const tagOpen = tag => `<${tag}>`

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function IsThisUndefined(props) {
  return <div>{props.title} {this === undefined ? 'Yes' : 'No'}!</div>
}

ReactDOM.render(
  <IsThisUndefined title='Is this undefined?' />,
  document.getElementById('app')
)

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class Counter extends React.Component {
    constructor(props) {
        super(props);
        this.state = {count: 0};
        this.incrementCounter = this.updateCounter.bind(this, 1);
        this.decrementCounter = this.updateCounter.bind(this, -1);
    }
    
    render() {
        return (

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// preserved from my comment in this issue: https://github.com/Microsoft/TypeScript/issues/165#issuecomment-259598080

interface Type<T> { new(...args): T }

interface CaseResult<R> {
    success: boolean;
    result: R;
}

interface CaseFn<R> { (value: any): CaseResult<R> }