web -> desktop

src/background/helpers/window.js

@@ -0,0 +1,84 @@
+// This helper remembers the size and position of your windows (and restores
+// them in that place after app relaunch).
+// Can be used for more than one window, just construct many
+// instances of it and give each different name.
+
+import { app, BrowserWindow, screen } from "electron";
+import jetpack from "fs-jetpack";
+
+export default (name, options) => {
+  const userDataDir = jetpack.cwd(app.getPath("userData"));
+  const stateStoreFile = `window-state-${name}.json`;
+  const defaultSize = {
+    width: options.width,
+    height: options.height
+  };
+  let state = {};
+  let win;
+
+  const restore = () => {
+    let restoredState = {};
+    try {
+      restoredState = userDataDir.read(stateStoreFile, "json");
+    } catch (err) {
+      // For some reason json can't be read (might be corrupted).
+      // No worries, we have defaults.
+    }
+    return Object.assign({}, defaultSize, restoredState);
+  };
+
+  const getCurrentPosition = () => {
+    const position = win.getPosition();
+    const size = win.getSize();
+    return {
+      x: position[0],
+      y: position[1],
+      width: size[0],
+      height: size[1]
+    };
+  };
+
+  const windowWithinBounds = (windowState, bounds) => {
+    return (
+      windowState.x >= bounds.x &&
+      windowState.y >= bounds.y &&
+      windowState.x + windowState.width <= bounds.x + bounds.width &&
+      windowState.y + windowState.height <= bounds.y + bounds.height
+    );
+  };
+
+  const resetToDefaults = () => {
+    const bounds = screen.getPrimaryDisplay().bounds;
+    return Object.assign({}, defaultSize, {
+      x: (bounds.width - defaultSize.width) / 2,
+      y: (bounds.height - defaultSize.height) / 2
+    });
+  };
+
+  const ensureVisibleOnSomeDisplay = windowState => {
+    const visible = screen.getAllDisplays().some(display => {
+      return windowWithinBounds(windowState, display.bounds);
+    });
+    if (!visible) {
+      // Window is partially or fully not visible now.
+      // Reset it to safe defaults.
+      return resetToDefaults();
+    }
+    return windowState;
+  };
+
+  const saveState = () => {
+    if (!win.isMinimized() && !win.isMaximized()) {
+      Object.assign(state, getCurrentPosition());
+    }
+    userDataDir.write(stateStoreFile, state, { atomic: true });
+  };
+
+  state = ensureVisibleOnSomeDisplay(restore());
+
+  win = new BrowserWindow(Object.assign({}, options, state));
+
+  win.on("close", saveState);
+
+  return win;
+};