1 files changed, 34 insertions, 0 deletions
diff --git a/src/components/DateString/compactDateString.ts b/src/components/DateString/compactDateString.ts
new file mode 100644
index 0000000..dffd912
--- /dev/null
+++ b/src/components/DateString/compactDateString.ts
@@ -0,0 +1,34 @@
+const metrics = [
+  { name: 'minute', ratio: 60 },
+  { name: 'hour', ratio: 60 },
+  { name: 'day', ratio: 24 },
+  { name: 'week', ratio: 7 },
+  { name: 'month', ratio: 4 },
+  { name: 'year', ratio: 12 }
+];
+
+const PRECISION = 0.75;
+
+const resolve = (value: number, metricIndex = 0): string => {
+  // Recursively divide value until it's ready to be presented as a string
+  const metric = metrics[metricIndex];
+  const nextMetric = metrics[metricIndex + 1];
+  const newValue = value / metric.ratio;
+
+  if (newValue < nextMetric.ratio * PRECISION) {
+    const rounded = Math.round(newValue);
+    const isPlural = rounded > 1;
+    const count = isPlural ? rounded : 'a';
+    const ending = isPlural ? 's' : '';
+    return `${count} ${metric.name}${ending} ago`;
+  }
+  return resolve(newValue, metricIndex + 1);
+};
+
+const compactDateString = (date: Date): string => {
+  const now = new Date();
+  const diff = (now.valueOf() - date.valueOf()) / 1000;
+  return resolve(diff);
+};
+
+export default compactDateString;