Fixups and style

* change 'data' state shape, nesting the tree fetcher data
* rename 'TreeFetcherParameters' from 'DatabaseParameters' to make it
more specific to the API it works on
* fix bug in 'equal' method of 'TreeFetcherParameters'`
* use mockTreeFetcherParameters method in tests that need to specify a
TreeFetcherParameters but when the value isn't relevant to the test
* Hide Resolver if there is no databaseDocumentID
* add doc comments

x-pack/plugins/security_solution/public/resolver/mocks/tree_fetcher_parameters.ts

@@ -0,0 +1,17 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { TreeFetcherParameters } from '../types';
+
+/**
+ * A factory for the most basic `TreeFetcherParameters`. Many tests need to provide this even when the values aren't relevant to the test.
+ */
+export function mockTreeFetcherParameters(): TreeFetcherParameters {
+  return {
+    databaseDocumentID: '',
+    indices: [],
+  };
+}

x-pack/plugins/security_solution/public/resolver/models/tree_fetcher_parameters.test.ts

@@ -0,0 +1,38 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { TreeFetcherParameters } from '../types';
+
+import { equal } from './tree_fetcher_parameters';
+describe('TreeFetcherParameters#equal:', () => {
+  const cases: Array<[TreeFetcherParameters, TreeFetcherParameters, boolean]> = [
+    // different databaseDocumentID
+    [{ databaseDocumentID: 'a', indices: [] }, { databaseDocumentID: 'b', indices: [] }, false],
+    // different indices length
+    [{ databaseDocumentID: 'a', indices: [''] }, { databaseDocumentID: 'a', indices: [] }, false],
+    // same indices length, different databaseDocumentID
+    [{ databaseDocumentID: 'a', indices: [''] }, { databaseDocumentID: 'b', indices: [''] }, false],
+    // 1 item in `indices`
+    [{ databaseDocumentID: 'b', indices: [''] }, { databaseDocumentID: 'b', indices: [''] }, true],
+    // 2 item in `indices`
+    [
+      { databaseDocumentID: 'b', indices: ['1', '2'] },
+      { databaseDocumentID: 'b', indices: ['1', '2'] },
+      true,
+    ],
+    // 2 item in `indices`, but order inversed
+    [
+      { databaseDocumentID: 'b', indices: ['2', '1'] },
+      { databaseDocumentID: 'b', indices: ['1', '2'] },
+      true,
+    ],
+  ];
+  describe.each(cases)('%p when compared to %p', (first, second, expected) => {
+    it(`should ${expected ? '' : 'not'}be equal`, () => {
+      expect(equal(first, second)).toBe(expected);
+    });
+  });
+});

x-pack/plugins/security_solution/public/resolver/models/tree_fetcher_parameters.ts

@@ -0,0 +1,40 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { TreeFetcherParameters } from '../types';
+
+/**
+ * Determine if two instances of `TreeFetcherParameters` are equivalent. Use this to determine if
+ * a change to a `TreeFetcherParameters` warrants invaliding a request or response.
+ */
+export function equal(param1: TreeFetcherParameters, param2?: TreeFetcherParameters): boolean {
+  if (!param2) {
+    return false;
+  }
+  if (param1 === param2) {
+    return true;
+  }
+  if (param1.databaseDocumentID !== param2.databaseDocumentID) {
+    return false;
+  }
+  return arrayEqual(param1.indices, param2.indices);
+}
+
+function arrayEqual(first: unknown[], second: unknown[]): boolean {
+  if (first === second) {
+    return true;
+  }
+  if (first.length !== second.length) {
+    return false;
+  }
+  const firstSet = new Set(first);
+  for (let index = 0; index < second.length; index++) {
+    if (!firstSet.has(second[index])) {
+      return false;
+    }
+  }
+  return true;
+}

x-pack/plugins/security_solution/public/resolver/store/data/action.ts

@@ -5,7 +5,7 @@
  */
 
 import { ResolverRelatedEvents, ResolverTree } from '../../../../common/endpoint/types';
-import { DatabaseParameters } from '../../types';
+import { TreeFetcherParameters } from '../../types';
 
 interface ServerReturnedResolverData {
   readonly type: 'serverReturnedResolverData';
@@ -17,7 +17,7 @@ interface ServerReturnedResolverData {
     /**
      * The database parameters that was used to fetch the resolver tree
      */
-    parameters: DatabaseParameters;
+    parameters: TreeFetcherParameters;
   };
 }
 
@@ -26,23 +26,23 @@ interface AppRequestedResolverData {
   /**
    * entity ID used to make the request.
    */
-  readonly payload: DatabaseParameters;
+  readonly payload: TreeFetcherParameters;
 }
 
 interface ServerFailedToReturnResolverData {
   readonly type: 'serverFailedToReturnResolverData';
   /**
    * entity ID used to make the failed request
    */
-  readonly payload: DatabaseParameters;
+  readonly payload: TreeFetcherParameters;
 }
 
 interface AppAbortedResolverDataRequest {
   readonly type: 'appAbortedResolverDataRequest';
   /**
    * entity ID used to make the aborted request
    */
-  readonly payload: DatabaseParameters;
+  readonly payload: TreeFetcherParameters;
 }
 
 /**

x-pack/plugins/security_solution/public/resolver/store/data/reducer.test.ts

@@ -12,6 +12,7 @@ import { DataState } from '../../types';
 import { DataAction } from './action';
 import { ResolverChildNode, ResolverTree } from '../../../../common/endpoint/types';
 import * as eventModel from '../../../../common/endpoint/models/event';
+import { mockTreeFetcherParameters } from '../../mocks/tree_fetcher_parameters';
 
 /**
  * Test the data reducer and selector.
@@ -27,7 +28,7 @@ describe('Resolver Data Middleware', () => {
         type: 'serverReturnedResolverData',
         payload: {
           result: tree,
-          parameters: { databaseDocumentID: '', indices: [] },
+          parameters: mockTreeFetcherParameters(),
         },
       };
       store.dispatch(action);

x-pack/plugins/security_solution/public/resolver/store/data/reducer.ts

@@ -7,41 +7,53 @@
 import { Reducer } from 'redux';
 import { DataState } from '../../types';
 import { ResolverAction } from '../actions';
-import * as databaseParameters from '../../models/database_parameters';
+import * as treeFetcherParameters from '../../models/tree_fetcher_parameters';
 
 const initialState: DataState = {
   relatedEvents: new Map(),
   relatedEventsReady: new Map(),
   resolverComponentInstanceID: undefined,
+  tree: {},
 };
 
 export const dataReducer: Reducer<DataState, ResolverAction> = (state = initialState, action) => {
   if (action.type === 'appReceivedNewExternalProperties') {
     const nextState: DataState = {
       ...state,
-      currentParameters: {
-        databaseDocumentID: action.payload.databaseDocumentID,
-        indices: action.payload.indices,
+      tree: {
+        ...state.tree,
+        currentParameters: {
+          databaseDocumentID: action.payload.databaseDocumentID,
+          indices: action.payload.indices,
+        },
       },
       resolverComponentInstanceID: action.payload.resolverComponentInstanceID,
     };
     return nextState;
   } else if (action.type === 'appRequestedResolverData') {
     // keep track of what we're requesting, this way we know when to request and when not to.
-    return {
+    const nextState: DataState = {
       ...state,
-      pendingRequestParameters: {
-        databaseDocumentID: action.payload.databaseDocumentID,
-        indices: action.payload.indices,
+      tree: {
+        ...state.tree,
+        pendingRequestParameters: {
+          databaseDocumentID: action.payload.databaseDocumentID,
+          indices: action.payload.indices,
+        },
       },
     };
+    return nextState;
   } else if (action.type === 'appAbortedResolverDataRequest') {
-    if (databaseParameters.equal(action.payload, state.pendingRequestParameters)) {
+    if (treeFetcherParameters.equal(action.payload, state.tree.pendingRequestParameters)) {
       // the request we were awaiting was aborted
-      return {
+      const nextState: DataState = {
         ...state,
-        pendingRequestParameters: undefined,
+        tree: {
+          ...state.tree,
+          pendingRequestParameters: undefined,
+        },
       };
+      return nextState;
     } else {
       return state;
     }
@@ -50,29 +62,35 @@ export const dataReducer: Reducer<DataState, ResolverAction> = (state = initialS
     const nextState: DataState = {
       ...state,
 
-      /**
-       * Store the last received data, as well as the databaseDocumentID it relates to.
-       */
-      lastResponse: {
-        result: action.payload.result,
-        parameters: action.payload.parameters,
-        successful: true,
-      },
+      tree: {
+        ...state.tree,
+        /**
+         * Store the last received data, as well as the databaseDocumentID it relates to.
+         */
+        lastResponse: {
+          result: action.payload.result,
+          parameters: action.payload.parameters,
+          successful: true,
+        },
 
-      // This assumes that if we just received something, there is no longer a pending request.
-      // This cannot model multiple in-flight requests
-      pendingRequestParameters: undefined,
+        // This assumes that if we just received something, there is no longer a pending request.
+        // This cannot model multiple in-flight requests
+        pendingRequestParameters: undefined,
+      },
     };
     return nextState;
   } else if (action.type === 'serverFailedToReturnResolverData') {
     /** Only handle this if we are expecting a response */
-    if (state.pendingRequestParameters !== undefined) {
+    if (state.tree.pendingRequestParameters !== undefined) {
       const nextState: DataState = {
         ...state,
-        pendingRequestParameters: undefined,
-        lastResponse: {
-          parameters: state.pendingRequestParameters,
-          successful: false,
+        tree: {
+          ...state.tree,
+          pendingRequestParameters: undefined,
+          lastResponse: {
+            parameters: state.tree.pendingRequestParameters,
+            successful: false,
+          },
         },
       };
       return nextState;
@@ -83,16 +101,18 @@ export const dataReducer: Reducer<DataState, ResolverAction> = (state = initialS
     action.type === 'userRequestedRelatedEventData' ||
     action.type === 'appDetectedMissingEventData'
   ) {
-    return {
+    const nextState: DataState = {
       ...state,
       relatedEventsReady: new Map([...state.relatedEventsReady, [action.payload, false]]),
     };
+    return nextState;
   } else if (action.type === 'serverReturnedRelatedEventData') {
-    return {
+    const nextState: DataState = {
       ...state,
       relatedEventsReady: new Map([...state.relatedEventsReady, [action.payload.entityID, true]]),
       relatedEvents: new Map([...state.relatedEvents, [action.payload.entityID, action.payload]]),
     };
+    return nextState;
   } else {
     return state;
   }