Masked API 400 error reason when streaming responses

[legraphista]

Environment details

• Programming language: typescript
• OS: ubuntu server 24.04
• Language runtime version: 22.9.0
• Package version: 0.4.0

Steps to reproduce

1. send a malformed request in streaming mode

Overview

When handling the error, there's a check for application/json in throwErrorIfNotOK

js-genai/src/_api_client.ts

Line 622 in f2df6d7

if (response.headers.get('content-type')?.includes('application/json')) {

This check fails since the content type is text/event-stream when streaming, and the error body is not handled at all:

js-genai/src/_api_client.ts

Lines 624 to 632 in f2df6d7

	} else {
	errorBody = {
	error: {
	message: 'exception parsing response',
	code: response.status,
	status: response.statusText,
	},
	};
	}

This masks the true error from being seen by the developer.

After applying the following patch, I could see what I was doing wrong:

async function throwErrorIfNotOK(response) {
    var _a;
    if (response === undefined) {
        throw new ServerError('response is undefined');
    }
    if (!response.ok) {
        const status = response.status;
        const statusText = response.statusText;
        let errorBody;
        if ((_a = response.headers.get('content-type')) === null || _a === void 0 ? void 0 : _a.includes('application/json')) {
            errorBody = await response.json();
        }
        else {
-           errorBody = {
-               error: {
-                   message: 'exception parsing response',
-                   code: response.status,
-                   status: response.statusText,
-               },
-           };
+           const text = await response.text();
+           errorBody = {
+               error: {
+                   message: text,
+                   code: response.status,
+                   status: response.statusText,
+               },
+           };
        }
        const errorMessage = `got status: ${status} ${statusText}. ${JSON.stringify(errorBody)}`;
        if (status >= 400 && status < 500) {
            const clientError = new ClientError(errorMessage);
            throw clientError;
        }
        else if (status >= 500 && status < 600) {
            const serverError = new ServerError(errorMessage);
            throw serverError;
        }
        throw new Error(errorMessage);
    }
}