Added byte truncate script to repo. Fixed yargs not enforcing choices.

src/utils/truncate-bytes.js

@@ -0,0 +1,23 @@
+'use strict';
+
+function truncateBytes(str, limit) {
+    if (Buffer.from(str).length <= limit) {
+        return str;
+    }
+
+    let acc = '';
+
+    for (let i = 0; i < str.length; i++) {
+        const newString = acc + str.charAt(i);
+
+        if (Buffer.from(newString).length > limit) {
+            break;
+        }
+
+        acc = newString;
+    }
+
+    return acc;
+}
+
+module.exports = truncateBytes;