Implement smart-date-format-helper

Add a helper that knows how to format past dates
in a smart way. When less than a week ago we will
use relative date strings - for dates older than a week
we will use a friendly human-readable format.

This matches best practices we want to adhere to
based on what Terraform did for date-formatting.

ui/packages/consul-ui/app/helpers/smart-date-format.js

@@ -0,0 +1,48 @@
+import Helper from '@ember/component/helper';
+import { inject as service } from '@ember/service';
+
+const MILLISECONDS_IN_DAY = 1000 * 60 * 60 * 24;
+const MILLISECONDS_IN_WEEK = MILLISECONDS_IN_DAY * 7;
+/**
+ * A function that returns if a date is within a week of the current time
+ * @param {*} date - the date to check
+ *
+ */
+function isNearDate(date) {
+  const now = new Date();
+  const aWeekAgo = now - MILLISECONDS_IN_WEEK;
+  const aWeekInFuture = now + MILLISECONDS_IN_WEEK;
+
+  return date >= aWeekAgo && aWeekInFuture;
+}
+
+export default class SmartDateFormat extends Helper {
+  @service temporal;
+  @service intl;
+
+  compute([value], hash) {
+    const fallback = hash.fallback || 'None yet';
+
+    if (!value) {
+      return {
+        isNearDate: false,
+        relative: fallback,
+        friendly: fallback,
+      };
+    }
+
+    return {
+      isNearDate: isNearDate(value),
+      relative: `${this.temporal.format(value)} ago`,
+      friendly: this.intl.formatTime(value, {
+        month: 'short',
+        day: 'numeric',
+        year: 'numeric',
+        hour: 'numeric',
+        minute: 'numeric',
+        second: 'numeric',
+        hourCycle: 'h24',
+      }),
+    };
+  }
+}