feat(extensions): implementation

webapp/packages/core/extensions/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@dbeaver/core/extensions",
+  "private": true,
+  "sideEffects": false,
+  "main": "../dist/extensions",
+  "module": "../dist/extensions",
+  "types": "../dist/types/extensions"
+}

webapp/packages/core/src/extensions/IExtension.ts

@@ -0,0 +1,15 @@
+/*
+ * cloudbeaver - Cloud Database Manager
+ * Copyright (C) 2020 DBeaver Corp and others
+ *
+ * Licensed under the Apache License, Version 2.0.
+ * you may not use this file except in compliance with the License.
+ */
+
+import { EXTENSION_SYMBOL, EXTENSION_TYPE_SYMBOL } from './constants';
+
+
+export interface IExtension<T> {
+  [EXTENSION_SYMBOL]: symbol;
+  [EXTENSION_TYPE_SYMBOL]?: T;
+}

webapp/packages/core/src/extensions/constants.ts

@@ -0,0 +1,10 @@
+/*
+ * cloudbeaver - Cloud Database Manager
+ * Copyright (C) 2020 DBeaver Corp and others
+ *
+ * Licensed under the Apache License, Version 2.0.
+ * you may not use this file except in compliance with the License.
+ */
+
+export const EXTENSION_SYMBOL = Symbol('@extension');
+export const EXTENSION_TYPE_SYMBOL = Symbol('@extension/type');

webapp/packages/core/src/extensions/createExtension.ts

@@ -0,0 +1,30 @@
+/*
+ * cloudbeaver - Cloud Database Manager
+ * Copyright (C) 2020 DBeaver Corp and others
+ *
+ * Licensed under the Apache License, Version 2.0.
+ * you may not use this file except in compliance with the License.
+ */
+
+import { EXTENSION_SYMBOL } from './constants';
+import { IExtension } from './IExtension';
+
+export function createExtension<T>(
+  extension: object,
+  key: symbol
+): IExtension<T> {
+  return Object.assign(extension, { [EXTENSION_SYMBOL]: key });
+}
+
+export function isExtension<T>(
+  obj: any,
+  key?: symbol,
+): obj is IExtension<T> {
+  if (!(EXTENSION_SYMBOL in obj)) {
+    return false;
+  }
+  if (key && obj[EXTENSION_SYMBOL] !== key) {
+    return false;
+  }
+  return true;
+}

webapp/packages/core/src/extensions/index.ts

@@ -0,0 +1,2 @@
+export * from './IExtension';
+export * from './createExtension';