improve persistable state types

x-pack/plugins/lens/public/editor_frame_plugin/plugin.tsx

@@ -33,7 +33,7 @@ class EditorFramePlugin {
         // on it's own because we are loosing type information here.
         // So it's basically explicitly saying "I'm dropping the information about type T here
         // because this information isn't useful to me." but without using any which can leak
-        this.datasources[name] = datasource as Datasource<unknown>;
+        this.datasources[name] = datasource as Datasource<unknown, unknown>;
       },
       registerVisualization: (name, visualization) => {
         this.visualizations[name] = visualization as Visualization<unknown>;

x-pack/plugins/lens/public/indexpattern_plugin/indexpattern.test.ts

@@ -4,11 +4,11 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { indexPatternDatasource } from './indexpattern';
+import { indexPatternDatasource, PersistableIndexPatternPrivateState } from './indexpattern';
 import { DatasourcePublicAPI, Operation } from '../types';
 
 describe('IndexPattern Data Source', () => {
-  let persistedState: object;
+  let persistedState: PersistableIndexPatternPrivateState;
 
   beforeEach(() => {
     persistedState = {
@@ -54,7 +54,7 @@ describe('IndexPattern Data Source', () => {
     it('should persist from saved state', async () => {
       const state = await indexPatternDatasource.initialize(persistedState);
 
-      expect(indexPatternDatasource.getPersistedState(state)).toEqual(persistedState);
+      expect(indexPatternDatasource.getPersistableState(state)).toEqual(persistedState);
     });
   });
 

x-pack/plugins/lens/public/indexpattern_plugin/indexpattern.tsx

@@ -49,9 +49,13 @@ export interface IndexPatternPrivateState {
   indexPatterns: { [id: string]: IndexPattern };
 }
 
+type PersistedKeys = 'currentIndexPattern' | 'columns' | 'columnOrder';
+
+export type PersistableIndexPatternPrivateState = Pick<IndexPatternPrivateState, PersistedKeys>;
+
 // Not stateful. State is persisted to the frame
-export const indexPatternDatasource: Datasource<IndexPatternPrivateState> = {
-  async initialize(state?: IndexPatternPrivateState | any) {
+export const indexPatternDatasource: Datasource<IndexPatternPrivateState, PersistableIndexPatternPrivateState> = {
+  async initialize(state?: PersistableIndexPatternPrivateState) {
     // TODO: Make fetch request to load indexPatterns from saved objects
     if (state) {
       return {
@@ -67,7 +71,7 @@ export const indexPatternDatasource: Datasource<IndexPatternPrivateState> = {
     };
   },
 
-  getPersistedState({ currentIndexPattern, columns, columnOrder }: IndexPatternPrivateState) {
+  getPersistableState({ currentIndexPattern, columns, columnOrder }: IndexPatternPrivateState) {
     return { currentIndexPattern, columns, columnOrder };
   },
 

x-pack/plugins/lens/public/types.ts

@@ -7,7 +7,7 @@
 export interface EditorFrameSetup {
   render: (domElement: Element) => void;
   // generic type on the API functions to pull the "unknown vs. specific type" error into the implementation
-  registerDatasource: <T>(name: string, datasource: Datasource<T>) => void;
+  registerDatasource: <T, P>(name: string, datasource: Datasource<T, P>) => void;
   registerVisualization: <T>(name: string, visualization: Visualization<T>) => void;
 }
 
@@ -37,12 +37,12 @@ export interface DatasourceSuggestion<T = unknown> {
 /**
  * Interface for the datasource registry
  */
-export interface Datasource<T = unknown> {
+export interface Datasource<T = unknown, P = unknown> {
   // For initializing, either from an empty state or from persisted state
-  initialize: (state?: T | any) => Promise<T>;
+  initialize: (state?: P) => Promise<T>;
 
-  // Given the current state, which parts should be saved?
-  getPersistedState: (state: T) => object;
+  // Return the subset of the state which should be persisted in a saved object
+  getPersistableState: (state: T) => P;
 
   renderDataPanel: (domElement: Element, props: DatasourceDataPanelProps<T>) => void;