Prerender Data Hook doesn't properly trigger errors on bad paths

[mririgoyen]

Do you want to request a feature or report a bug?
Bug

What is the current behaviour?

Using the prerender hook, if the URL it is trying to get the preact_prerender_data.json file does not exist, it does not properly report an error. This is because the function to get the data is asynchronous but the function is called and then immediately returned. See:

preact-cli/packages/prerender-data-provider/src/hook.js

Line 47 in 52333a5

fetchPreRenderData();

What is the expected behaviour?

The error value is reported as true via the hook interface.

Please mention other relevant information.

Environment Info:
  System:
    OS: macOS 11.2.1
    CPU: (12) x64 Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
  Binaries:
    Node: 14.15.4 - ~/.nvm/versions/node/v14.15.4/bin/node
    Yarn: 1.22.10 - ~/.nvm/versions/node/v14.15.4/bin/yarn
    npm: 7.5.2 - ~/.nvm/versions/node/v14.15.4/bin/npm
  Browsers:
    Chrome: 88.0.4324.150
    Edge: 88.0.705.68
    Firefox: 85.0
    Safari: 14.0.3
  npmPackages:
    preact: ^10.3.2 => 10.5.12
    preact-cli: ^3.0.0 => 3.0.5
    preact-render-to-string: ^5.1.4 => 5.1.12
    preact-router: ^3.2.1 => 3.2.1
  npmGlobalPackages:
    preact-cli: 3.0.5