live-fns: add xo badges (#154)

I like having xo badges on my repos. :D

/cc @sindresorhus

libs/index.md

@@ -260,6 +260,11 @@ Advanced usage (for badge makers):
       ['(past month) uptime', '/uptime-robot/month/m780862024-50db2c44c703e5c68d6b1ebb'],
       ['(last hours) response', '/uptime-robot/response/m780862024-50db2c44c703e5c68d6b1ebb']
     ],
+    xo: [
+      ['status', '/xo/status/badgen'],
+      ['indent', '/xo/indent/@tusbar/cache-control'],
+      ['semicolons', '/xo/semi/got']
+    ],
     badgesize: [
       ['normal size', '/badgesize/normal/amio/emoji.json/master/emoji-compact.json'],
       ['brotli size', '/badgesize/brotli/amio/emoji.json/master/emoji-compact.json'],

libs/live-fns/_index.js

@@ -29,5 +29,6 @@ module.exports = {
   runkit: require('./runkit.js'),
   travis: require('./travis.js'),
   'uptime-robot': require('./uptime-robot.js'),
-  'vs-marketplace': require('./vs-marketplace.js')
+  'vs-marketplace': require('./vs-marketplace.js'),
+  xo: require('./xo')
 }

libs/live-fns/xo.js

@@ -0,0 +1,49 @@
+const got = require('../got.js')
+
+const getIndent = space => {
+  if (space === false) return 'tab'
+  if (space === true) return '2 spaces'
+  if (space === 1) return '1 space'
+  return `${space} spaces`
+}
+
+module.exports = async (topic, ...project) => {
+  const endpoint = `https://cdn.jsdelivr.net/npm/${project.join('/')}/package.json`
+  const data = await got(endpoint).then(res => res.body)
+
+  if (!data.devDependencies || !('xo' in data.devDependencies)) {
+    return {
+      subject: 'xo',
+      status: 'not enabled',
+      color: 'grey'
+    }
+  }
+
+  const {
+    semicolon = true,
+    space = false
+  } = (data.xo || {})
+
+  switch (topic) {
+    case 'status':
+      return {
+        subject: 'xo',
+        status: 'enabled',
+        color: '5ED9C7'
+      }
+
+    case 'indent':
+      return {
+        subject: 'indent',
+        status: getIndent(space),
+        color: '5ED9C7'
+      }
+
+    case 'semi':
+      return {
+        subject: 'semicolons',
+        status: semicolon ? 'enabled' : 'disabled',
+        color: '5ED9C7'
+      }
+  }
+}