1 files changed, 55 insertions, 0 deletions

diff --git a/language-web/src/main/js/editor/xtextMessages.ts b/language-web/src/main/js/editor/xtextMessages.ts
new file mode 100644
index 00000000..d3cb9425
--- /dev/null
+++ b/language-web/src/main/js/editor/xtextMessages.ts
@@ -0,0 +1,55 @@
+export interface IXtextWebRequest {
+  id: string;
+
+  request: unknown;
+}
+
+export interface IXtextWebOkResponse {
+  id: string;
+
+  response: unknown;
+}
+
+export function isOkResponse(response: unknown): response is IXtextWebOkResponse {
+  const okResponse = response as IXtextWebOkResponse;
+  return typeof okResponse.id === 'string'
+    && typeof okResponse.response !== 'undefined';
+}
+
+export const VALID_XTEXT_WEB_ERROR_KINDS = ['request', 'server'] as const;
+
+export type XtextWebErrorKind = typeof VALID_XTEXT_WEB_ERROR_KINDS[number];
+
+export interface IXtextWebErrorResponse {
+  id: string;
+
+  error: XtextWebErrorKind;
+
+  message: string;
+}
+
+export function isErrorResponse(response: unknown): response is IXtextWebErrorResponse {
+  const errorResponse = response as IXtextWebErrorResponse;
+  return typeof errorResponse.id === 'string'
+    && typeof errorResponse.error === 'string'
+    && VALID_XTEXT_WEB_ERROR_KINDS.includes(errorResponse.error)
+    && typeof errorResponse.message === 'string';
+}
+
+export interface IXtextWebPushMessage {
+  resource: string;
+
+  stateId: string;
+
+  service: string;
+
+  push: unknown;
+}
+
+export function isPushMessage(response: unknown): response is IXtextWebPushMessage {
+  const pushMessage = response as IXtextWebPushMessage;
+  return typeof pushMessage.resource === 'string'
+    && typeof pushMessage.stateId === 'string'
+    && typeof pushMessage.service === 'string'
+    && typeof pushMessage.push !== 'undefined';
+}