Import file menu command

Derived from https://github.com/swagger-api/swagger-editor/blob/master/src/standalone/topbar-menu-file-import_file/components/ImportFileMenuItem.jsx

src/main/commands.ts

@@ -0,0 +1,31 @@
+import {BrowserWindow, dialog} from 'electron'
+import { promises as fs } from 'fs'
+
+import { dump, load } from "js-yaml"
+import isJsonObject from "is-json"
+
+function updateSpec(window, content) {
+  const preparedContent = isJsonObject(content) ? dump(load(content)) : content
+
+  window.webContents.send('update-spec', preparedContent);
+}
+
+export async function importFile() {
+  const window = BrowserWindow.getFocusedWindow()
+  const selected = await dialog.showOpenDialog({
+    filters: [
+      { name: 'OpenAPI', extensions: ['json', 'yml', 'yaml'] },
+      { name: 'All Files', extensions: ['*'] }
+    ],
+    properties: ['openFile']
+  })
+
+  if (!selected.canceled) {
+    try {
+      const content = (await fs.readFile(selected.filePaths[0])).toString()
+      updateSpec(window, content)
+    } catch(e) {
+      dialog.showErrorBox('Error loading file', `Oof! There was an error loading your document:\n\n${e.message || e}`)
+    }
+  }
+}

src/main/menus.ts

@@ -1,8 +1,22 @@
 import { Menu, shell } from 'electron'
 
+import { importFile } from "./commands";
+
+const isMac = process.platform === 'darwin'
+
 const template = [
   { role: 'appMenu'},
-  { role: 'fileMenu' },
+  {
+    label: 'File',
+    submenu: [
+      {
+        label: 'Import file',
+        click: importFile
+      },
+      { type: 'separator' },
+      isMac ? { role: 'close' } : { role: 'quit' }
+    ]
+  },
   { role: 'editMenu' },
   { role: 'viewMenu' },
   { role: 'windowMenu' },