Add /_stats endpoint

Also, remove ingest_stats worker and use the cache instead.

client/utils/addEvent.js

@@ -0,0 +1,9 @@
+const addEvent = (node, type, handler) => {
+  if (node.addEventListener) {
+    node.addEventListener(type, handler, false)
+  } else if (node.attachEvent) {
+    node.attachEvent('on' + type, handler)
+  }
+}
+
+export default addEvent

client/utils/formatNumber.js

@@ -0,0 +1,11 @@
+const formatNumber = (n) => {
+  const digits = String(n).split('')
+  const groups = []
+
+  while (digits.length)
+    groups.unshift(digits.splice(-3).join(''))
+
+  return groups.join(',')
+}
+
+export default formatNumber

client/utils/formatPercent.js

@@ -0,0 +1,4 @@
+const formatPercent = (n, fixed = 1) =>
+  String((n.toPrecision(2) * 100).toFixed(fixed))
+
+export default formatPercent

client/utils/parseNumber.js

@@ -0,0 +1,4 @@
+const parseNumber = (s) =>
+  parseInt(s.replace(/,/g, ''), 10) || 0
+
+export default parseNumber

client/utils/removeEvent.js

@@ -0,0 +1,9 @@
+const removeEvent = (node, type, handler) => {
+  if (node.removeEventListener) {
+    node.removeEventListener(type, handler, false)
+  } else if (node.detachEvent) {
+    node.detachEvent('on' + type, handler)
+  }
+}
+
+export default removeEvent