Indentation error

match-media.js

@@ -0,0 +1,112 @@
+const matchMediaFallback = () => {
+  let listeners = []
+  let idle = true
+
+  const device = (() => {
+    let node = document.createElement('div')
+    let style = document.createElement('style')
+
+    node.id = 'match-media-node'
+    style.innerHTML = `#match-media-node {
+      width: 100%;
+      height: 100%;
+      position: absolute;
+      bottom: 100%;
+      overflow: scroll;
+    }`
+
+    document.head.appendChild(style)
+    document.body.insertBefore(node, document.body.children[0])
+
+    return {
+      get width() {
+        return node.clientWidth
+      },
+      get height() {
+        return node.clientHeight
+      },
+      get orientation() {
+        return (node.clientHeight > node.clientWidth)
+          ? 'portrait'
+          : 'landscape'
+      },
+      get fontSize() {
+        return window
+          .getComputedStyle(document.documentElement)
+          .getPropertyValue('font-size')
+      }
+    }
+  })()
+
+  const createHandler = (feature, value) => {
+    if (feature === 'orientation') {
+      return () => value === device.orientation
+    }
+
+    let [prop, limit] = feature
+      .split('-')
+      .reverse()
+
+    const operand = (!limit) ? '=='
+      : (limit === 'min') ? '<'
+        : '>'
+
+    const parseValue = (() => {
+      return (~value.indexOf('em'))
+        ? () => parseFloat(value) * device.fontSize
+        : () => parseFloat(value)
+    })()
+
+    const handlers = {
+      'width': () => eval(parseValue() + operand + device.width),
+      'height': () => eval(parseValue() + operand + device.height)
+    }
+
+    return handlers[prop]
+  }
+
+  const parseQuery = (queryString) => {
+    let [feature, value] = queryString.replace(/[()\s]/g, '').split(':')
+    return createHandler(feature, value)
+  }
+
+  window.addEventListener('resize', () => {
+    if (!idle) return;
+    idle = false
+
+    let width = device.width
+    let height = device.height
+
+    let timer = setInterval(() => {
+      if (width !== device.width || height !== device.height) {
+        width = device.width
+        height = device.height
+      } else {
+        clearTimeout(timer)
+        listeners.forEach(handler => handler())
+        idle = true
+      }
+    }, 100)
+  })
+
+  return (queryString) => {
+    const query = parseQuery(queryString)
+    const matcher = {
+      get matches() {
+        return query()
+      }
+    }
+
+    return {
+      ...matcher,
+      addListener(cb) {
+        const handler = () => cb(matcher)
+        listeners.push(handler)
+      }
+    }
+  }
+}
+
+const matchMedia = window.matchMedia || matchMediaFallback()
+
+export { matchMedia as default }