Merged PR 16: Transform every single class components into functional component

This improve greatly the performance and the code cleaning.
It allows us to separate the inseparable class methods into modules functions

src/Components/Editor/Shortcuts.ts

@@ -0,0 +1,23 @@
+import { Dispatch, SetStateAction } from 'react';
+import { HistoryState } from "../../Interfaces/HistoryState";
+
+export function onKeyDown(
+  event: KeyboardEvent,
+  history: HistoryState[],
+  historyCurrentStep: number,
+  setHistoryCurrentStep: Dispatch<SetStateAction<number>>
+): void {
+  event.preventDefault();
+  if (event.isComposing || event.keyCode === 229) {
+    return;
+  }
+  if (event.key === 'z' &&
+        event.ctrlKey &&
+        historyCurrentStep > 0) {
+    setHistoryCurrentStep(historyCurrentStep - 1);
+  } else if (event.key === 'y' &&
+              event.ctrlKey &&
+              historyCurrentStep < history.length - 1) {
+    setHistoryCurrentStep(historyCurrentStep + 1);
+  }
+}