eventyay: Instructions file for GitHub Copilot

Development Standards

Modernization

• Do not use jQuery
• Use ES modules, not IIFEs.
• Implement as external scripts; do not use inline scripts because they are blocked by CSP.

Error handling

• Always log errors with contextual information. You may skip this when letting the error bubble up to be handled by a higher-level component or function.

• Use try/catch blocks in async functions to handle exceptions gracefully. You may skip this when letting the error bubble up to be handled by a higher-level component or function, but you must add a comment documenting that the function may throw errors. For example:

  /**
  * @throws {HTTPError} when the network request fails
  */
  async function fetchData() {
    const response = await ky.get('/some-endpoint')
    return response.json()
  }
  

• When working with a library that provides its own error types (such as ky with HTTPError), do not replace this specific error type with a generic one. For example, do not do this:

  try {
    await ky.get('/some-endpoint')
  } catch (error) {
    throw new Error('Failed to fetch data') // Bad: replacing HTTPError with generic Error
  }
  

  Instead, let the error bubble up (with a comment), or do this:

  try {
    await ky.get('/some-endpoint')
  } catch (error) {
    if (error instanceof HTTPError) {
      // Handle HTTPError specifically
      throw error // Re-throw the original error
    }
    throw new Error('An unexpected error occurred') // Handle other errors
  }
  

• Do not create empty catch blocks.

DOM access

• Be careful when using .closest(selector) because it makes the page fragile to DOM changes. Choose a selector carefully so that the code does not break when the DOM changes.

Comments

• Do not add a comment when the code is already obvious and the comment is almost the same as the code.

Frontend Code Locations

Path	Purpose
app/eventyay/static/	Static assets served by Django (CSS, legacy JS)
app/eventyay/webapp/	Modern JS applications (Vue 3, built with a bundler)