Implement critical path JS

CONTRIBUTING.md

@@ -143,3 +143,11 @@ You'll need to update these every now and then when you change something in the
 ```
 yarn run critical
 ```
+
+## Critical path JS
+
+There's JavaScript that's included inline in every page. It's entrypoint is:
+
+- `_js/critical.js`
+
+This is automatically compiled into the partial `_includes/2017/critical/critical.js`. Keep this bundle as small as possible.

_includes/2017/critical/critical.js

@@ -0,0 +1 @@
+!function(e){function n(r){if(t[r])return t[r].exports;var o=t[r]={i:r,l:!1,exports:{}};return e[r].call(o.exports,o,o.exports,n),o.l=!0,o.exports}var t={};n.m=e,n.c=t,n.d=function(e,t,r){n.o(e,t)||Object.defineProperty(e,t,{configurable:!1,enumerable:!0,get:r})},n.n=function(e){var t=e&&e.__esModule?function(){return e.default}:function(){return e};return n.d(t,"a",t),t},n.o=function(e,n){return Object.prototype.hasOwnProperty.call(e,n)},n.p="",n(n.s=2)}([function(e,n){function t(e,n){var t=e.matches||e.matchesSelector||e.msMatchesSelector||e.mozMatchesSelector||e.webkitMatchesSelector||e.oMatchesSelector;if(t)return t.call(e,n);if(e.parentNode){for(var r=e.parentNode.querySelectorAll(n),o=r.length;o--;0)if(r[o]===e)return!0;return!1}}e.exports=t},function(e,n,t){function r(e,n){if(n){if(Array.isArray(n))return void o(n,function(n){r(e,n)});if(e.classList){var t=n.split(" ").filter(Boolean);o(t,function(n){e.classList.add(n)})}else e.className+=" "+n}}var o=t(4);e.exports=r},function(e,n,t){"use strict";function r(e){return e&&e.__esModule?e:{default:e}}var o=t(3),i=r(o),u=t(1),a=r(u),c=document.querySelector("[data-js-main-body]");c&&((0,i.default)(c),(0,a.default)(c,"-wrapified"))},function(e,n,t){"use strict";function r(e){return e&&e.__esModule?e:{default:e}}function o(e){if(Array.isArray(e)){for(var n=0,t=Array(e.length);n<e.length;n++)t[n]=e[n];return t}return Array.from(e)}function i(e){u(e).forEach(function(e){(0,p.findChildren)(e,"[data-js-h3-section-list]").forEach(function(e){a(e)})})}function u(e){return c(e,{tag:"h2",wrapperFn:function(){return(0,p.createDiv)({class:"h2-section"})},bodyFn:function(){return(0,p.createDiv)({class:"body h3-section-list","data-js-h3-section-list":""})}})}function a(e){return c(e,{tag:"h3",wrapperFn:function(){return(0,p.createDiv)({class:"h3-section"})},bodyFn:function(){return(0,p.createDiv)({class:"body"})}})}function c(e,n){function t(e,n,t){var r=i(),o=e.className;o&&(0,d.default)(r,o),(0,p.before)(e,r);var a=u();return o&&(0,d.default)(a,o),(0,p.appendMany)(a,t),n&&r.appendChild(n),r.appendChild(a),r}var r=n.tag,i=n.wrapperFn,u=n.bodyFn,a=e.children[0],c=[];if(a&&!(0,l.default)(a,r)){var f=(0,p.nextUntil)(a,r);c.push(t(a,null,[a].concat(o(f))))}return(0,p.findChildren)(e,r).forEach(function(e){var n=(0,p.nextUntil)(e,r);c.push(t(e,e,n))}),c}Object.defineProperty(n,"__esModule",{value:!0}),n.default=i,n.groupify=c;var f=t(0),l=r(f),s=t(1),d=r(s),p=t(5)},function(e,n){function t(e,n){var t,r,o=e.length;if("number"==typeof o)for(t=0;t<o;t++)n(e[t],t);else{r=0;for(t in e)e.hasOwnProperty(t)&&n(e[t],t,r++)}return e}e.exports=t},function(e,n,t){"use strict";function r(e){if(Array.isArray(e)){for(var n=0,t=Array(e.length);n<e.length;n++)t[n]=e[n];return t}return Array.from(e)}function o(e,n){n.forEach(function(n){e.appendChild(n)})}function i(e,n){return u(e.nextSibling,n,[])}function u(e,n,t){return e?(0,s.default)(e,n)?t:u(e.nextSibling,n,[].concat(r(t),[e])):t}function a(e,n){e.parentNode.insertBefore(n,e)}function c(e,n){return[].slice.call(e.children).filter(function(e){return(0,s.default)(e,n)})}function f(e){var n=document.createElement("div");return Object.keys(e).forEach(function(t){n.setAttribute(t,e[t])}),n}Object.defineProperty(n,"__esModule",{value:!0}),n.appendMany=o,n.nextUntil=i,n.before=a,n.findChildren=c,n.createDiv=f;var l=t(0),s=function(e){return e&&e.__esModule?e:{default:e}}(l)}]);

_includes/2017/foot.html

@@ -0,0 +1,5 @@
+<!-- critical js -->
+<script>{% include 2017/critical/critical.js %}</script>
+{% for lang in page.prism_languages %}<script src='https://cdn.jsdelivr.net/npm/prismjs@1.6.0/components/prism-{{lang}}.min.js'></script>{% endfor %}
+<script src='{{base}}/assets/packed/vendor.js?t={{ timestamp }}'></script>
+<script src='{{base}}/assets/packed/app.js?t={{ timestamp }}'></script>

_includes/2017/head.html

@@ -1,19 +1,16 @@
 {% include meta.html %}
 {% include polyfills.html %}
 
-<script src='{{base}}/assets/packed/vendor.js?t={{ timestamp }}'></script>
-<script src='{{base}}/assets/packed/app.js?t={{ timestamp }}'></script>
-{% for lang in page.prism_languages %}<script src='https://cdn.jsdelivr.net/npm/prismjs@1.6.0/components/prism-{{lang}}.min.js'></script>{% endfor %}
+<!-- critical css -->
+{% if include.critical == 'home'
+%}<style>{% include 2017/critical/home.css %}</style>{%
+endif
+%}{%
+if include.critical == 'sheet'
+%}<style>{% include 2017/critical/sheet.css %}</style>{%
+endif %}
 
-{% if include.critical == 'home' %}
-<style>{% include 2017/critical/home.html %}</style>
-{% endif %}
-
-{% if include.critical == 'sheet' %}
-<style>{% include 2017/critical/sheet.html %}</style>
-{% endif %}
-
-<!-- css -->
+<!-- deferred css -->
 <script>;(function(links){(requestAnimationFrame||mozRequestAnimationFrame||webkitRequestAnimationFrame||msRequestAnimationFrame||(function(fn){window.addEventListener('load',fn)}))(function(){var h=document.getElementsByTagName('head')[0],l,i;for (i=0;i<links.length;i++){l=document.createElement('link');l.rel='stylesheet';l.href=links[i];h.appendChild(l);}})})([
 'https://fonts.googleapis.com/css?family=Cousine',
 '{{base}}/assets/2017/style.css?t={{ timestamp }}'

_js/critical.js

@@ -0,0 +1,14 @@
+/*
+ * This is the "critical path" JavaScript that will be included INLINE on every
+ * page. Keep this as small as possible!
+ */
+
+import wrapify from './wrapify'
+import addClass from 'dom101/add-class'
+
+const body = document.querySelector('[data-js-main-body]')
+
+if (body) {
+  wrapify(body)
+  addClass(body, '-wrapified')
+}

_js/initializers/onmount.js

@@ -1,17 +1,10 @@
-import wrapify from '../wrapify'
 import ready from 'dom101/ready'
 import onmount from 'onmount'
-import addClass from 'dom101/add-class'
 
 /**
  * Behavior: Wrapping
  */
 
 ready(() => {
-  const body = document.querySelector('[data-js-main-body]')
-  if (body) {
-    wrapify(body)
-    addClass(body, '-wrapified')
-  }
   setTimeout(() => { onmount() })
 })

_sass/2017/style.scss

@@ -1,3 +1,4 @@
+@import '../vendor/sanitize.css/sanitize';
 @import './variables';
 @import '../vendor/modularscale/modularscale';
 @import '../vendor/ionicons-inline/ionicons';

_sass/vendor/sanitize.css/sanitize.scss

@@ -0,0 +1,589 @@
+/*! sanitize.css v5.0.0 | CC0 License | github.com/jonathantneal/sanitize.css */
+
+/* Document (https://html.spec.whatwg.org/multipage/semantics.html#semantics)
+   ========================================================================== */
+
+/**
+ * 1. Remove repeating backgrounds in all browsers (opinionated).
+ * 2. Add box sizing inheritence in all browsers (opinionated).
+ */
+
+*,
+::before,
+::after {
+	background-repeat: no-repeat; /* 1 */
+	box-sizing: inherit; /* 2 */
+}
+
+/**
+ * 1. Add text decoration inheritance in all browsers (opinionated).
+ * 2. Add vertical alignment inheritence in all browsers (opinionated).
+ */
+
+::before,
+::after {
+	text-decoration: inherit; /* 1 */
+	vertical-align: inherit; /* 2 */
+}
+
+/**
+ * 1. Add border box sizing in all browsers (opinionated).
+ * 2. Add the default cursor in all browsers (opinionated).
+ * 3. Prevent font size adjustments after orientation changes in IE and iOS.
+ */
+
+html {
+	box-sizing: border-box; /* 1 */
+	cursor: default; /* 2 */
+	-ms-text-size-adjust: 100%; /* 3 */
+	-webkit-text-size-adjust: 100%; /* 3 */
+}
+
+/* Sections (https://html.spec.whatwg.org/multipage/semantics.html#sections)
+   ========================================================================== */
+
+/**
+ * Add the correct display in IE 9-.
+ */
+
+article,
+aside,
+footer,
+header,
+nav,
+section {
+	display: block;
+}
+
+/**
+ * Remove the margin in all browsers (opinionated).
+ */
+
+body {
+	margin: 0;
+}
+
+/**
+ * Correct the font size and margin on `h1` elements within `section` and
+ * `article` contexts in Chrome, Firefox, and Safari.
+ */
+
+h1 {
+	font-size: 2em;
+	margin: .67em 0;
+}
+
+/* Grouping content (https://html.spec.whatwg.org/multipage/semantics.html#grouping-content)
+   ========================================================================== */
+
+/**
+ * Add the correct display in IE 9-.
+ * 1. Add the correct display in IE.
+ */
+
+figcaption,
+figure,
+main { /* 1 */
+	display: block;
+}
+
+/**
+ * Add the correct margin in IE 8.
+ */
+
+figure {
+	margin: 1em 40px;
+}
+
+/**
+ * 1. Add the correct box sizing in Firefox.
+ * 2. Show the overflow in Edge and IE.
+ */
+
+hr {
+	box-sizing: content-box; /* 1 */
+	height: 0; /* 1 */
+	overflow: visible; /* 2 */
+}
+
+/**
+ * Remove the list style on navigation lists in all browsers (opinionated).
+ */
+
+nav ol,
+nav ul {
+	list-style: none;
+}
+
+/**
+ * 1. Correct the inheritance and scaling of font size in all browsers.
+ * 2. Correct the odd `em` font sizing in all browsers.
+ */
+
+pre {
+	font-family: monospace, monospace; /* 1 */
+	font-size: 1em; /* 2 */
+}
+
+/* Text-level semantics (https://html.spec.whatwg.org/multipage/semantics.html#text-level-semantics)
+   ========================================================================== */
+
+/**
+ * 1. Remove the gray background on active links in IE 10.
+ * 2. Remove gaps in links underline in iOS 8+ and Safari 8+.
+ */
+
+a {
+	background-color: transparent; /* 1 */
+	-webkit-text-decoration-skip: objects; /* 2 */
+}
+
+/**
+ * 1. Remove the bottom border in Firefox 39-.
+ * 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
+ */
+
+abbr[title] {
+	border-bottom: none; /* 1 */
+	text-decoration: underline; /* 2 */
+	text-decoration: underline dotted; /* 2 */
+}
+
+/**
+ * Prevent the duplicate application of `bolder` by the next rule in Safari 6.
+ */
+
+b,
+strong {
+	font-weight: inherit;
+}
+
+/**
+ * Add the correct font weight in Chrome, Edge, and Safari.
+ */
+
+b,
+strong {
+	font-weight: bolder;
+}
+
+/**
+ * 1. Correct the inheritance and scaling of font size in all browsers.
+ * 2. Correct the odd `em` font sizing in all browsers.
+ */
+
+code,
+kbd,
+samp {
+	font-family: monospace, monospace; /* 1 */
+	font-size: 1em; /* 2 */
+}
+
+/**
+ * Add the correct font style in Android 4.3-.
+ */
+
+dfn {
+	font-style: italic;
+}
+
+/**
+ * Add the correct background and color in IE 9-.
+ */
+
+mark {
+	background-color: #ffff00;
+	color: #000000;
+}
+
+/**
+ * Add the correct font size in all browsers.
+ */
+
+small {
+	font-size: 80%;
+}
+
+/**
+ * Prevent `sub` and `sup` elements from affecting the line height in
+ * all browsers.
+ */
+
+sub,
+sup {
+	font-size: 75%;
+	line-height: 0;
+	position: relative;
+	vertical-align: baseline;
+}
+
+sub {
+	bottom: -.25em;
+}
+
+sup {
+	top: -.5em;
+}
+
+/*
+ * Remove the text shadow on text selections (opinionated).
+ * 1. Restore the coloring undone by defining the text shadow (opinionated).
+ */
+
+::-moz-selection {
+	background-color: #b3d4fc; /* 1 */
+	color: #000000; /* 1 */
+	text-shadow: none;
+}
+
+::selection {
+	background-color: #b3d4fc; /* 1 */
+	color: #000000; /* 1 */
+	text-shadow: none;
+}
+
+/* Embedded content (https://html.spec.whatwg.org/multipage/embedded-content.html#embedded-content)
+   ========================================================================== */
+
+/*
+ * Change the alignment on media elements in all browers (opinionated).
+ */
+
+audio,
+canvas,
+iframe,
+img,
+svg,
+video {
+	vertical-align: middle;
+}
+
+/**
+ * Add the correct display in IE 9-.
+ */
+
+audio,
+video {
+	display: inline-block;
+}
+
+/**
+ * Add the correct display in iOS 4-7.
+ */
+
+audio:not([controls]) {
+	display: none;
+	height: 0;
+}
+
+/**
+ * Remove the border on images inside links in IE 10-.
+ */
+
+img {
+	border-style: none;
+}
+
+/**
+ * Change the fill color to match the text color in all browsers (opinionated).
+ */
+
+svg {
+	fill: currentColor;
+}
+
+/**
+ * Hide the overflow in IE.
+ */
+
+svg:not(:root) {
+	overflow: hidden;
+}
+
+/* Tabular data (https://html.spec.whatwg.org/multipage/tables.html#tables)
+   ========================================================================== */
+
+/**
+ * Collapse border spacing
+ */
+
+table {
+	border-collapse: collapse;
+}
+
+/* Forms (https://html.spec.whatwg.org/multipage/forms.html#forms)
+   ========================================================================== */
+
+/**
+ * Remove the margin in Firefox and Safari.
+ */
+
+button,
+input,
+optgroup,
+select,
+textarea {
+	margin: 0;
+}
+
+/**
+ * Inherit styling in all browsers (opinionated).
+ */
+
+button,
+input,
+select,
+textarea {
+	background-color: transparent;
+	color: inherit;
+	font-size: inherit;
+	line-height: inherit;
+}
+
+/**
+ * Show the overflow in IE.
+ * 1. Show the overflow in Edge.
+ */
+
+button,
+input { /* 1 */
+	overflow: visible;
+}
+
+/**
+ * Remove the inheritance of text transform in Edge, Firefox, and IE.
+ * 1. Remove the inheritance of text transform in Firefox.
+ */
+
+button,
+select { /* 1 */
+	text-transform: none;
+}
+
+/**
+ * 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
+ *    controls in Android 4.
+ * 2. Correct the inability to style clickable types in iOS and Safari.
+ */
+
+button,
+html [type="button"], /* 1 */
+[type="reset"],
+[type="submit"] {
+	-webkit-appearance: button; /* 2 */
+}
+
+/**
+ * Remove the inner border and padding in Firefox.
+ */
+
+button::-moz-focus-inner,
+[type="button"]::-moz-focus-inner,
+[type="reset"]::-moz-focus-inner,
+[type="submit"]::-moz-focus-inner {
+	border-style: none;
+	padding: 0;
+}
+
+/**
+ * Restore the focus styles unset by the previous rule.
+ */
+
+button:-moz-focusring,
+[type="button"]:-moz-focusring,
+[type="reset"]:-moz-focusring,
+[type="submit"]:-moz-focusring {
+	outline: 1px dotted ButtonText;
+}
+
+/**
+ * 1. Correct the text wrapping in Edge and IE.
+ * 2. Correct the color inheritance from `fieldset` elements in IE.
+ * 3. Remove the padding so developers are not caught out when they zero out
+ *    `fieldset` elements in all browsers.
+ */
+
+legend {
+	box-sizing: border-box; /* 1 */
+	color: inherit; /* 2 */
+	display: table; /* 1 */
+	max-width: 100%; /* 1 */
+	padding: 0; /* 3 */
+	white-space: normal; /* 1 */
+}
+
+/**
+ * 1. Add the correct display in IE 9-.
+ * 2. Add the correct vertical alignment in Chrome, Firefox, and Opera.
+ */
+
+progress {
+	display: inline-block; /* 1 */
+	vertical-align: baseline; /* 2 */
+}
+
+/**
+ * 1. Remove the default vertical scrollbar in IE.
+ * 2. Change the resize direction on textareas in all browsers (opinionated).
+ */
+
+textarea {
+	overflow: auto; /* 1 */
+	resize: vertical; /* 2 */
+}
+
+/**
+ * 1. Add the correct box sizing in IE 10-.
+ * 2. Remove the padding in IE 10-.
+ */
+
+[type="checkbox"],
+[type="radio"] {
+	box-sizing: border-box; /* 1 */
+	padding: 0; /* 2 */
+}
+
+/**
+ * Correct the cursor style of increment and decrement buttons in Chrome.
+ */
+
+[type="number"]::-webkit-inner-spin-button,
+[type="number"]::-webkit-outer-spin-button {
+	height: auto;
+}
+
+/**
+ * 1. Correct the odd appearance in Chrome and Safari.
+ * 2. Correct the outline style in Safari.
+ */
+
+[type="search"] {
+	-webkit-appearance: textfield; /* 1 */
+	outline-offset: -2px; /* 2 */
+}
+
+/**
+ * Remove the inner padding and cancel buttons in Chrome and Safari on macOS.
+ */
+
+[type="search"]::-webkit-search-cancel-button,
+[type="search"]::-webkit-search-decoration {
+	-webkit-appearance: none;
+}
+
+/**
+ * 1. Correct the inability to style clickable types in iOS and Safari.
+ * 2. Change font properties to `inherit` in Safari.
+ */
+
+::-webkit-file-upload-button {
+	-webkit-appearance: button; /* 1 */
+	font: inherit; /* 2 */
+}
+
+/* Interactive elements (https://html.spec.whatwg.org/multipage/forms.html#interactive-elements)
+   ========================================================================== */
+
+/*
+ * Add the correct display in IE 9-.
+ * 1. Add the correct display in Edge, IE, and Firefox.
+ */
+
+details, /* 1 */
+menu {
+	display: block;
+}
+
+/*
+ * Add the correct display in all browsers.
+ */
+
+summary {
+	display: list-item;
+}
+
+/* Scripting (https://html.spec.whatwg.org/multipage/scripting.html#scripting-3)
+   ========================================================================== */
+
+/**
+ * Add the correct display in IE 9-.
+ */
+
+canvas {
+	display: inline-block;
+}
+
+/**
+ * Add the correct display in IE.
+ */
+
+template {
+	display: none;
+}
+
+/* User interaction (https://html.spec.whatwg.org/multipage/interaction.html#editing)
+   ========================================================================== */
+
+/*
+ * Remove the tapping delay on clickable elements (opinionated).
+ * 1. Remove the tapping delay in IE 10.
+ */
+
+a,
+area,
+button,
+input,
+label,
+select,
+summary,
+textarea,
+[tabindex] {
+	-ms-touch-action: manipulation; /* 1 */
+	touch-action: manipulation;
+}
+
+/**
+ * Add the correct display in IE 10-.
+ */
+
+[hidden] {
+	display: none;
+}
+
+/* ARIA (https://w3c.github.io/html-aria/)
+   ========================================================================== */
+
+/**
+ * Change the cursor on busy elements (opinionated).
+ */
+
+[aria-busy="true"] {
+	cursor: progress;
+}
+
+/*
+ * Change the cursor on control elements (opinionated).
+ */
+
+[aria-controls] {
+	cursor: pointer;
+}
+
+/*
+ * Change the display on visually hidden accessible elements (opinionated).
+ */
+
+[aria-hidden="false"][hidden]:not(:focus) {
+	clip: rect(0, 0, 0, 0);
+	display: inherit;
+	position: absolute;
+}
+
+/*
+ * Change the cursor on disabled, not-editable, or otherwise
+ * inoperable elements (opinionated).
+ */
+
+[aria-disabled] {
+	cursor: default;
+}

_support/critical.js

@@ -16,13 +16,13 @@ const options = {
 critical.generate({
   ...options,
   src: 'index.html',
-  dest: '../_includes/2017/critical/home.html'
+  dest: '../_includes/2017/critical/home.css'
 })
 
 critical.generate({
   ...options,
   src: 'react.html',
-  dest: '../_includes/2017/critical/sheet.html',
+  dest: '../_includes/2017/critical/sheet.css',
   include: [
     /\.h3-section/
   ]

_support/webpack.config.js

@@ -19,7 +19,6 @@ module.exports = {
       'prismjs/components/prism-ruby.min.js',
 
       // CSS
-      'sanitize.css',
       'prismjs/plugins/line-highlight/prism-line-highlight.css',
       'hint.css/hint.min.css'
     ]

_support/webpack.critical.js

@@ -0,0 +1,28 @@
+const join = require('path').resolve
+const webpack = require('webpack')
+
+module.exports = {
+  context: join(__dirname, '..'),
+  entry: './_js/critical.js',
+  output: {
+    path: join(__dirname, '..', '_includes', '2017', 'critical'),
+    filename: 'critical.js'
+  },
+  module: {
+    rules: [
+      {
+        test: /\.js$/,
+        exclude: /node_modules/,
+        use: [
+          { loader: 'babel-loader' }
+        ]
+      }
+    ]
+  },
+  stats: 'minimal',
+  plugins: [
+    new webpack.EnvironmentPlugin({
+      NODE_ENV: 'production'
+    })
+  ]
+}

webpack.config.js

@@ -1 +1,4 @@
-module.exports = require('./_support/webpack.config.js')
+module.exports = [
+  require('./_support/webpack.config.js'),
+  require('./_support/webpack.critical.js')
+]