fix: Throw unkown function error code when function not found in module.

Support returning falsy values from a juno function

Author: thebongy

src/juno-node.ts

@@ -3,7 +3,7 @@ import { promises as fsPromises } from 'fs';
 import { BaseProtocol } from './protocol/base-protocol';
 import BaseConnection from './connection/base-connection';
 import { JsonProtocol } from './protocol/json-protocol';
-import { ResponseTypes, RequestTypes } from './utils/constants';
+import { ResponseTypes, RequestTypes, ErrorTypes } from './utils/constants';
 import {
 	FunctionCallRequest,
 	FunctionCallResponse,
@@ -12,6 +12,7 @@ import {
 } from './models/messages';
 import UnixSocketConnection from './connection/unix-socket-connection';
 import InetSocketConnection from './connection/inet-socket-connection';
+import {JunoError} from './models/errors';
 
 export default class JunoModule {
 
@@ -139,54 +140,72 @@ export default class JunoModule {
 		}
 
 		return new Promise((resolve, reject) => {
-			this.requests[request.requestId] = (response: any) => {
-				if (response) {
-					resolve(response);
+			this.requests[request.requestId] = (err: boolean | Error, response: any) => {
+				if (err) {
+					reject(err);
 				} else {
-					reject(response);
+					resolve(response);
 				}
 			};
 		});
 	}
 
 	private async onDataHandler(data: Buffer) {
 		const response = this.protocol.decode(data);
-		let value;
+		let value: any = true;
+		let err: boolean | Error = false;
 		switch (response.type) {
 			case ResponseTypes.ModuleRegistered: {
-				value = true;
+				err = false;
 				break;
 			}
 			case ResponseTypes.FunctionResponse: {
+				err = false;
 				value = (response as FunctionCallResponse).data;
 				break;
 			}
 			case ResponseTypes.FunctionDeclared: {
-				value = true;
+				err = false;
 				break;
 			}
 			case ResponseTypes.HookRegistered: {
-				value = true;
+				err = false;
 				break;
 			}
 			case ResponseTypes.HookTriggered: {
-				value = await this.executeHookTriggered(response as TriggerHookRequest);
+				try {
+					await this.executeHookTriggered(response as TriggerHookRequest);
+					err = false;
+				} catch (e) {
+					err = e;
+				}
 				break;
 			}
 
 			case RequestTypes.FunctionCall: {
-				this.executeFunctionCall(response as FunctionCallRequest);
+				try {
+					await this.executeFunctionCall(response as FunctionCallRequest);
+				} catch (e) {
+					err = e;
+				}
 				break;
 			}
 
 			default: {
-				value = false;
-				break;
+				err = TypeError("Error message/Invalid message received from juno");
 			}
 		}
 
+		if (err instanceof JunoError) {
+			this.sendRequest({
+				requestId: response.requestId,
+				type: ResponseTypes.Error,
+				error: err.errCode,
+			});
+		}
+		
 		if (this.requests[response.requestId]) {
-			this.requests[response.requestId](value);
+			this.requests[response.requestId](err, value);
 			delete this.requests[response.requestId];
 		}
 	}
@@ -202,10 +221,9 @@ export default class JunoModule {
 				type: ResponseTypes.FunctionResponse,
 				data: res || {}
 			});
-			return true;
 		} else {
 			// Function wasn't found in the module.
-			return false;
+			throw new JunoError(ErrorTypes.UnkownFunction);
 		}
 	}
 
@@ -222,10 +240,6 @@ export default class JunoModule {
 					listener(request.data || {});
 				}
 			}
-			return true;
-		} else {
-			// This moddule triggered the hook.
-			return true;
-		}
+		}	
 	}
 }

src/models/errors.ts

@@ -0,0 +1,11 @@
+export class JunoError extends Error {
+    errCode: number;
+    constructor(errCode: number) {
+        super(`Juno Error: ${errCode}`);
+	this.errCode = errCode;
+
+        // Set the prototype explicitly.
+        Object.setPrototypeOf(this, JunoError.prototype);
+    }
+}
+

src/models/messages.ts

@@ -52,12 +52,17 @@ export interface DeclareFunctionResponse extends BaseMessage {
 	function: string;
 }
 
+export interface ErrorResponse extends BaseMessage {
+	error: number;
+}
+
 export type JunoResponse =
 	RegisterModuleResponse |
 	ListenHookResponse |
 	TriggerHookResponse |
 	DeclareFunctionResponse |
-	FunctionCallResponse;
+	FunctionCallResponse |
+	ErrorResponse;
 export type JunoRequest =
 	RegisterModuleRequest |
 	DeclareFunctionRequest |
@@ -74,4 +79,5 @@ export type JunoMessage =
 	DeclareFunctionRequest |
 	FunctionCallRequest |
 	RegisterHookRequest |
-	TriggerHookRequest;
+	TriggerHookRequest |
+	ErrorResponse;

src/utils/constants.ts

@@ -19,9 +19,21 @@ export const RequestTypes = {
 };
 
 export const ResponseTypes = {
+	Error: 0,
 	ModuleRegistered: 2,
 	FunctionResponse: 4,
 	HookRegistered: 6,
 	HookTriggered: 8,
 	FunctionDeclared: 10
 };
+
+export const ErrorTypes = {
+	MalformedRequest: 0,
+	InvalidRequestId: 1,
+	UnkownRequest: 2,
+	UnregisteredModule: 3,
+	UnkownModule: 4,
+	UnkownFunction: 5,
+	InvalidModuleId: 6,
+	DuplicateModule: 7,
+};