Extract components and shapes into their respective modules (#212)

src/components/ButtonSelect.tsx

@@ -0,0 +1,25 @@
+import React from "react";
+
+export function ButtonSelect<T>({
+  options,
+  value,
+  onChange
+}: {
+  options: { value: T; text: string }[];
+  value: T | null;
+  onChange: (value: T) => void;
+}) {
+  return (
+    <div className="buttonList">
+      {options.map(option => (
+        <button
+          key={option.text}
+          onClick={() => onChange(option.value)}
+          className={value === option.value ? "active" : ""}
+        >
+          {option.text}
+        </button>
+      ))}
+    </div>
+  );
+}