Add className & text content utilities

Author: timolins

src/utils.ts

@@ -0,0 +1,8 @@
+import { DecorationType } from "./types";
+
+export const classNames = (...classes: Array<string | undefined | false>) =>
+  classes.filter(a => !!a).join(" ");
+
+export const getTextContent = (text: DecorationType[]) => {
+  return text.reduce((prev, current) => prev + current[0], "");
+};