cy.task('seedDb') failed with the following error: The task 'seedDb' was not handled in the setupNodeEvents method.

Why this happens

• The task was never registered with `on('task', { ... })` inside `setupNodeEvents`
• The name used in `cy.task()` doesn't exactly match the key in the `on('task')` object (typo or different casing)
• `on('task', ...)` is called more than once, and a plugin's call replaced your task map instead of merging with it
• The config was changed while Cypress was open and the Node process hasn't reloaded it

How to fix it

1. Register the task in `setupNodeEvents` in cypress.config.ts and check the key matches the name in `cy.task()`
2. Merge all tasks into a single `on('task', { ...pluginTasks, ...yourTasks })` call rather than calling `on('task')` from several plugins
3. Make sure the handler returns a value or `null`, never `undefined`, or Cypress will fail the task for a different reason
4. Restart Cypress after editing the config file

Example

              // cypress.config.ts
export default defineConfig({
  e2e: {
    setupNodeEvents(on) {
      on('task', {
        async seedDb() {
          await resetDatabase();
          return null; // tasks must not return undefined
        },
      });
    },
  },
});