custom error classes (#601)

* custom error classes

* throw error when act, extract, observe are called instead of immediately

* revert removal (should be done in separate PR)

* rm dumb comments

* changeset

* more errors

* global default error on init, act, extract, observe

* minor

* more errors

Author: seanmcguire12

Diff for: .changeset/four-hoops-mix.md

@@ -0,0 +1,5 @@
+---
+"@browserbasehq/stagehand": minor
+---
+
+add custom error classes

Diff for: evals/index.eval.ts

@@ -31,6 +31,7 @@ import { EvalLogger } from "./logger";
 import { AvailableModel } from "@/dist";
 import { env } from "./env";
 import dotenv from "dotenv";
+import { StagehandEvalError } from "@/types/stagehandErrors";
 dotenv.config();
 
 /**
@@ -226,8 +227,8 @@ const generateFilteredTestcases = (): Testcase[] => {
           const taskFunction = taskModule[input.name];
 
           if (typeof taskFunction !== "function") {
-            throw new Error(
-              `Task function for ${input.name} is not a function`,
+            throw new StagehandEvalError(
+              `No Eval function found for task name: ${input.name}`,
             );
           }
 

Diff for: evals/taskConfig.ts

@@ -14,6 +14,7 @@ import fs from "fs";
 import path from "path";
 import { AvailableModel, AvailableModelSchema } from "@/dist";
 import { filterByEvalName } from "./args";
+import { UnsupportedModelError } from "@/types/stagehandErrors";
 
 // The configuration file `evals.config.json` contains a list of tasks and their associated categories.
 const configPath = path.join(__dirname, "evals.config.json");
@@ -62,7 +63,7 @@ const getModelList = (): string[] => {
 };
 const MODELS: AvailableModel[] = getModelList().map((model) => {
   if (!AvailableModelSchema.safeParse(model).success) {
-    throw new Error(`Model ${model} is not a supported model`);
+    throw new UnsupportedModelError(getModelList(), "Running evals");
   }
   return model as AvailableModel;
 });

Diff for: evals/tasks/peeler_simple.ts

@@ -1,5 +1,6 @@
 import { EvalFunction } from "@/types/evals";
 import { initStagehand } from "@/evals/initStagehand";
+import { StagehandEnvironmentError } from "@/types/stagehandErrors";
 
 const env: "BROWSERBASE" | "LOCAL" =
   process.env.EVAL_ENV?.toLowerCase() === "browserbase"
@@ -15,8 +16,10 @@ export const peeler_simple: EvalFunction = async ({ modelName, logger }) => {
   const { debugUrl, sessionUrl } = initResponse;
 
   if (env === "BROWSERBASE") {
-    throw new Error(
-      "Browserbase not supported for this eval since we block all requests to file://",
+    throw new StagehandEnvironmentError(
+      "BROWSERBASE",
+      "LOCAL",
+      "peeler_simple eval",
     );
   }
 

Diff for: examples/external_clients/ollama.ts

@@ -26,6 +26,7 @@ import type {
   ChatCompletionUserMessageParam,
 } from "openai/resources/chat/completions";
 import { z } from "zod";
+import { CreateChatCompletionResponseError } from "@/types/stagehandErrors";
 
 function validateZodSchema(schema: z.ZodTypeAny, data: unknown) {
   try {
@@ -226,7 +227,7 @@ export class OllamaClient extends LLMClient {
     if (options.response_model) {
       const extractedData = response.choices[0].message.content;
       if (!extractedData) {
-        throw new Error("No content in response");
+        throw new CreateChatCompletionResponseError("No content in response");
       }
       const parsedData = JSON.parse(extractedData);
 
@@ -239,7 +240,7 @@ export class OllamaClient extends LLMClient {
           });
         }
 
-        throw new Error("Invalid response schema");
+        throw new CreateChatCompletionResponseError("Invalid response schema");
       }
 
       return parsedData;