Error Handling

To handle exceptions that may arise while using the library, osu.js provides the OsuJSGeneralError and OsuJSUnexpectedResponseError classes and a type of OsuJSError. The classes are thrown in the same way as the native Error class while type is simple a union of both of these classes.

class OsuJSGeneralError extends Error { ... }
class OsuJSUnexpectedResponseError extends Error { ... }

type OsuJSError = OsuJSGeneralError | OsuJSUnexpectedResponseError;

To determine whether an error comes from osu.js, use the isOsuJSError utility function inside your catch block.

Example

import { isOsuJSError } from 'osu-web.js';

try {
  const user = await api.users.getUser(14544646, {
    urlParams: {
      mode: 'osu'
    }
  });
} catch (err) {
  if (isOsuJSError(err)) {
    // `err` is now of type `OsuJSError`

    if (err.type === 'invalid_json_syntax') {
      // `err` is now of type `OsuJSGeneralError`
      console.error('Error while parsing response as JSON');
    } else if (err.type === 'network_error') {
      // `err` is now of type `OsuJSGeneralError`
      console.error('Network error');
    } else if (err.type === 'unexpected_response') {
      // `err` is now of type `OsuJSUnexpectedResponseError`

      /**
       * If using the fetch polyfill instead of the native fetch API, write:
       * `err.response(true)`
       * "true" means that it will return the Response type from "node-fetch" instead of the native Response
       */
      const response = err.response(); // Type: `Response`

      console.error('Unexpected response');
      console.log(`Details: ${response.status} - ${response.statusText}`);
      consoe.log('JSON: ', await response.json());
    }
  }
}

Error Types

Type	Upon	Message
undefined_fetch	Initializing clients	Global fetch is undefined. Please provide a polyfill for the fetch API by installing “node-fetch”
invalid_json_syntax	Requesting API	A syntax error occurred while trying to parse the response as JSON. The API returned invalid JSON
network_error	Requesting API	A network error occurred while making a request to the API
unexpected_response	Requesting API	Received an unexpected response from the API

Notice that something is missing? Found a typo? Think something's incomplete? Or think that something can be explained better? Feel free to open a pull request or submit an issue on the library's Github repository .