add some comments

x-pack/plugins/endpoint/public/embeddables/resolver/models/process_event.ts

@@ -6,10 +6,17 @@
 
 import { ProcessEvent } from '../types';
 
+/*
+ * Returns true is the process's eventType is either 'processCreated' or 'processRan'.
+ * Resolver will only render 'graphable' process events.
+ */
 export function isGraphableProcess(event: ProcessEvent) {
   return eventType(event) === 'processCreated' || eventType(event) === 'processRan';
 }
 
+/*
+ * Returns a custom event type for a process event based on the event's metadata.
+ */
 export function eventType(event: ProcessEvent) {
   const {
     data_buffer: { event_type_full: type, event_subtype_full: subType },
@@ -31,10 +38,16 @@ export function eventType(event: ProcessEvent) {
   return 'unknownEvent';
 }
 
+/*
+ * Returns the process event's pid
+ */
 export function uniquePidForProcess(event: ProcessEvent) {
   return event.data_buffer.node_id;
 }
 
+/*
+ * Returns the process event's parent pid
+ */
 export function uniqueParentPidForProcess(event: ProcessEvent) {
   return event.data_buffer.source_id;
 }

x-pack/plugins/endpoint/public/embeddables/resolver/models/process_event_test_helpers.ts

@@ -7,6 +7,12 @@
 import { ProcessEvent } from '../types';
 type DeepPartial<T> = { [K in keyof T]?: DeepPartial<T[K]> };
 
+/*
+ * Creates a mock process event given the 'parts' argument, which can
+ * include all or some process event fields as determined by the ProcessEvent type.
+ * The only field that must be provided is the event's 'node_id' field.
+ * The other fields are populated by the function unless provided in 'parts'
+ */
 export function mockProcessEvent(
   parts: {
     data_buffer: { node_id: ProcessEvent['data_buffer']['node_id'] };

x-pack/plugins/endpoint/public/embeddables/resolver/store/data/selectors.ts

@@ -29,6 +29,23 @@ import {
 const unit = 100;
 const distanceBetweenNodesInUnits = 1;
 
+/* An isometric projection is a method for representing three dimensional objects in 2 dimensions.
+ * More information about isometric projections can be found here https://en.wikipedia.org/wiki/Isometric_projection.
+ * In our case, we obtain the isometric projection by rotating the objects 45 degrees in the plane of the screen
+ * and arctan(1/sqrt(2)) (~35.3 degrees) through the horizontal axis.
+ *
+ * A rotation by 45 degrees in the plane of the screen is given by:
+ * [ sqrt(2)/2   -sqrt(2)/2   0
+ *   sqrt(2)/2    sqrt(2)/2   0
+ *   0            0           1]
+ *
+ * A rotation by arctan(1/sqrt(2)) through the horizantal axis is given by:
+ * [ 1      0          0
+ *   0      sqrt(3)/3  -sqrt(6)/3
+ *   0      sqrt(6)/3  sqrt(3)/3]
+ *
+ * We can multiply both of these matrices to get the final transformation below.
+ */
 /* prettier-ignore */
 const isometricTransformMatrix: Matrix3 = [
   Math.sqrt(2) / 2,   -(Math.sqrt(2) / 2),  0,