diff --git a/src/parsers/dart-json/dart-json-types.ts b/src/parsers/dart-json/dart-json-types.ts
new file mode 100644
index 0000000..e5b34b8
--- /dev/null
+++ b/src/parsers/dart-json/dart-json-types.ts
@@ -0,0 +1,129 @@
+/// reflects documentation at https://github.com/dart-lang/test/blob/master/pkgs/test/doc/json_reporter.md
+
+export type ReportEvent =
+  | StartEvent
+  | AllSuitesEvent
+  | SuiteEvent
+  | DebugEvent
+  | GroupEvent
+  | TestStartEvent
+  | TestDoneEvent
+  | DoneEvent
+  | MessageEvent
+  | ErrorEvent
+
+export interface Event {
+  type: 'start' | 'allSuites' | 'suite' | 'debug' | 'group' | 'testStart' | 'print' | 'error' | 'testDone' | 'done'
+  time: number
+}
+
+export interface StartEvent extends Event {
+  type: 'start'
+  protocolVersion: string
+  runnerVersion: string
+  pid: number
+}
+
+export interface AllSuitesEvent extends Event {
+  type: 'allSuites'
+  count: number // The total number of suites that will be loaded.
+}
+
+export interface SuiteEvent extends Event {
+  type: 'suite'
+  suite: Suite
+}
+
+export interface GroupEvent extends Event {
+  type: 'group'
+  group: Group
+}
+
+export interface TestStartEvent extends Event {
+  type: 'testStart'
+  test: Test
+}
+
+export interface TestDoneEvent extends Event {
+  type: 'testDone'
+  testID: number
+  result: 'success' | 'failure' | 'error'
+  hidden: boolean
+  skipped: boolean
+}
+
+export interface DoneEvent extends Event {
+  type: 'done'
+  success: boolean
+}
+
+export interface ErrorEvent extends Event {
+  type: 'error'
+  testID: number
+  error: string
+  stackTrace: string
+  isFailure: boolean
+}
+
+export interface DebugEvent extends Event {
+  type: 'debug'
+  suiteID: number
+  observatory: string
+  remoteDebugger: string
+}
+
+export interface MessageEvent extends Event {
+  type: 'print'
+  testID: number
+  messageType: string
+  message: string
+}
+
+export interface Suite {
+  id: number
+  platform?: string
+  path: string
+}
+
+export interface Group {
+  id: number
+  name?: string
+  suiteID: number
+  parentID?: number
+  testCount: number
+  line: number | null // The (1-based) line on which the group  was defined, or `null`.
+  column: number | null // The (1-based) column on which the group  was defined, or `null`.
+  url: string | null
+}
+
+export interface Test {
+  id: number
+  name: string
+  suiteID: number
+  groupIDs: number[] // The IDs of groups containing this test, in order from outermost to innermost.
+  line: number | null // The (1-based) line on which the test was defined, or `null`.
+  column: number | null // The (1-based) column on which the test was defined, or `null`.
+  url: string | null
+  root_line?: number
+  root_column?: number
+  root_url: string | undefined
+}
+
+export function isSuiteEvent(event: Event): event is SuiteEvent {
+  return event.type === 'suite'
+}
+export function isGroupEvent(event: Event): event is GroupEvent {
+  return event.type === 'group'
+}
+export function isTestStartEvent(event: Event): event is TestStartEvent {
+  return event.type === 'testStart'
+}
+export function isTestDoneEvent(event: Event): event is TestDoneEvent {
+  return event.type === 'testDone'
+}
+export function isErrorEvent(event: Event): event is ErrorEvent {
+  return event.type === 'error'
+}
+export function isDoneEvent(event: Event): event is DoneEvent {
+  return event.type === 'done'
+}