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              <div class="mdl-layout__container">
  <div class="mdl-grid mdl-grid__max-width">
    <div class="mdl-card mdl-card__wide mdl-shadow--4dp">
      <div class="mdl-card__title mdl-color--accent">
        <h2 class="mdl-card__title-text">Functional App</h2>
      <div id="post-container" class="mdl-card__supporting-text">
        <div class="mdl-progress mdl-js-progress mdl-progress__indeterminate"></div>
              .mdl-layout {
  &__container {
    margin-top: 2em;
    margin-bottom: 2em;

.mdl-grid {
  &__max-width {
    max-width: 640px;
    margin: auto;
.mdl-card {
  &__wide {
    width: 100%;

              const {curry, compose, map} = R
// pure
const url      = ""
const postsUrl = _ => `${url}/posts`
const join     = x => x.join('')
const prop     = s => obj => obj[s]
const theTitle = compose(prop('rendered'), prop('title'))
const span     = s => `<span class="mdl-list__item-primary-content">${s}</span>`
const li       = s => `<li class="mdl-list__item">${s}</li>`
const ul       = s => `<ul id="post-list" class="mdl-list">${s}</ul>`
const listItem = compose(li, span)
// impure 
const fetchJson  = fn => url => $.getJSON(url).then(fn)
const setHtml    = el => html => $(el).html(html)
const inspect    = label => x => (console.log(label, x), x)
// specialization 
const updatePostContainer = setHtml('#post-container')
const titleToList = map(compose(listItem,theTitle))
// app composition 
const render       = compose(updatePostContainer, ul, join, titleToList)
const executeApp   = compose(fetchJson(render), postsUrl)
// run the app