Enable Virtual Module Resolution

Overview

To implement a custom resolution system that allows resolving virtual modules and handles cases where files have not been created yet, you can extend the Metro resolver with a custom resolveRequest function. This function will provide a VirtualResolution for modules that don’t exist physically but are dynamically generated or virtualized.

resolveRequest?: CustomResolver;

export type CustomResolver = (
  context: CustomResolutionContext,
  moduleName: string,
  platform: string | null,
) => Resolution;

export type Resolution = FileResolution | VirtualResolution 
 | Readonly<{type: 'empty'}>;

export type FileResolution = AssetResolution | SourceFileResolution;

export type AssetResolution = Readonly<{
  type: 'assetFiles';
  filePaths: AssetFileResolution;
}>;

export type SourceFileResolution = Readonly<{
  type: 'sourceFile';
  filePath: string;
}>;

export type VirtualResolution = Readonly<{
  type: 'virtual';
  content: string;
}>;

Start by tracing Metro's custom resolveRequest hook and the Resolution types shown in the issue. Review how existing file, asset, and empty resolutions are handled, then define and test the behavior for a virtual resolution whose content comes from a module that does not exist on disk.