refactor: modularize frontend flows

src/utils/clipboard-paste.ts

@@ -0,0 +1,40 @@
+export const getClipboardFile = (items: DataTransferItemList): File | null => {
+  for (let index = 0; index < items.length; index++) {
+    const item = items[index]
+    if (item.kind !== 'file') {
+      continue
+    }
+
+    const file = item.getAsFile()
+    if (file) {
+      return file
+    }
+  }
+  return null
+}
+
+export type TextInsertionInput = {
+  text: string
+  insertText: string
+  selectionStart: number
+  selectionEnd: number
+}
+
+export type TextInsertionResult = {
+  value: string
+  cursor: number
+}
+
+export const insertTextAtSelection = ({
+  text,
+  insertText,
+  selectionStart,
+  selectionEnd
+}: TextInsertionInput): TextInsertionResult => {
+  const beforeSelection = text.substring(0, selectionStart)
+  const afterSelection = text.substring(selectionEnd)
+  return {
+    value: beforeSelection + insertText + afterSelection,
+    cursor: selectionStart + insertText.length
+  }
+}