Make punctuate translatable, rename to punctuateSeries

js/lib/helpers/punctuateSeries.js

@@ -0,0 +1,35 @@
+/**
+ * The `punctuateSeries` helper formats a list of strings (e.g. names) to read
+ * fluently in the application's locale.
+ *
+ * ```js
+ * punctuateSeries(['Toby', 'Franz', 'Dominion']) // Toby, Franz, and Dominion
+ * ```
+ *
+ * @param {Array} items
+ * @return {VirtualElement}
+ */
+export default function punctuateSeries(items) {
+  if (items.length === 2) {
+    return app.trans('core.lib.series_two_text', {
+      first: items[0],
+      second: items[1]
+    });
+  } else if (items.length >= 3) {
+    // If there are three or more items, we will join all of the items up until
+    // the second-to-last one with the equivalent of a comma, and then we will
+    // feed that into the translator along with the last two items.
+    const first = items
+      .slice(0, items.length - 2)
+      .reduce((list, item) => list.concat([item, app.trans('core.lib.series_glue_text')]), [])
+      .slice(0, -1);
+
+    return app.trans('core.lib.series_three_text', {
+      first,
+      second: items[items.length - 2],
+      third: items[items.length - 1]
+    });
+  }
+
+  return items;
+}