Fastboot Support is Soft Deprecated

[runspired]

related: ember-fastboot/ember-cli-fastboot#913

Due to removal of the hack to load ember-fetch which is itself incompatible with modern ember and embroider, applications building with fastboot and using ember-data no longer have the ability to issue requests due to lacking APIs that should be available on the global.

ember-fetch support was removed in #8473
Fastboot request tests have been deactivated in #8472

As long as AbortController is unneeded and only legacy EmberData network fetching is used Fastboot will continue to work until removal of Adapter and Serializer codepaths in 6.0, which should occur ~ Fall 2023

This soft deprecations is because while EmberData is happy to continue testing against and supporting a healthy SSR project that enables use of ecosystem standards, we don't have time to maintain such an SSR solution ourselves.

[runspired]

For using Fastboot with EmberData

<app>/config/fastboot.js

/* global ReadableStream, WritableStream, TransformStream */
module.exports = function (environment) {
  return {
    buildSandboxGlobals(defaultGlobals) {
      return Object.assign({}, defaultGlobals, {
        AbortController,
        ReadableStream:
          typeof ReadableStream !== 'undefined' ? ReadableStream : require('node:stream/web').ReadableStream,
        WritableStream:
          typeof WritableStream !== 'undefined' ? WritableStream : require('node:stream/web').WritableStream,
        TransformStream:
          typeof TransformStream !== 'undefined' ? TransformStream : require('node:stream/web').TransformStream,
        Headers: typeof Headers !== 'undefined' ? Headers : undefined,
      });
    },
  };
};

For using with ember-cli-fastboot-testing

config/fastboot-testing.js

/* global ReadableStream, WritableStream, TransformStream */
module.exports = {
  buildSandboxGlobals(defaultGlobals) {
    return Object.assign({}, defaultGlobals, {
      AbortController,
      ReadableStream:
        typeof ReadableStream !== 'undefined' ? ReadableStream : require('node:stream/web').ReadableStream,
      WritableStream:
        typeof WritableStream !== 'undefined' ? WritableStream : require('node:stream/web').WritableStream,
      TransformStream:
        typeof TransformStream !== 'undefined' ? TransformStream : require('node:stream/web').TransformStream,
      Headers: typeof Headers !== 'undefined' ? Headers : undefined,
    });
  },
};

Additionally global fetch will override EmberData's Fastboot.require('node-fetch') if present, so adding fetch to the sandbox "just works".