rollup-plugin-hypothetical

This allows Rollup modules to import hypothetical files passed in as options to the plugin.

Installation

npm install --save-dev rollup-plugin-hypothetical

Usage

// rollup.config.js
import hypothetical from 'rollup-plugin-hypothetical';

export default {
  entry: './dir/a.js',
  plugins: [hypothetical({
    files: {
      './dir/a.js': `
        import foo from './b.js';
        foo();
      `,
      './dir/b.js': `
        import message from 'external';
        export default function foo() {
          console.log(message);
        }
      `,
      'external/': `
        export default "Hello, World!";
      `
    }
  })]
};

Sourcemaps

To attach a sourcemap to a hypothetical file, simply pass in a { code, map } object instead of a string. The sourcemap can have its own sources, sourcesContent, etc.

Options

options.files

An object whose keys are paths, either relative to the current working directory or absolute, and whose values are the code within the hypothetical files at those paths.

options.filesMap

Rather than supplying a plain object to options.files, you may choose to supply a Map to options.filesMap. This will allow you to do things like naming your hypothetical files __proto__.

options.allowFallthrough

Defaults to false. Set this to true to allow non-external imports to fall through. That way they can be handled either by Rollup's default behavior (reading from the filesystem) or by a plugin further down the chain if there is one.

options.allowExternalFallthrough

Defaults to true. Set this to false to forbid external imports from falling through.

options.allowRelativeExternalFallthrough

Defaults to false. Set this to true to allow relative imports from supplied external modules to fall through. For instance, suppose you have the following options.files:

{
  './main.js': `
    import 'external/x.js';
  `,
  'external/x.js': `
    import './y.js';
  `
}

The supplied file external/x.js imports external/y.js, but external/y.js isn't supplied. This sort of thing is probably a mistake. If it isn't, set options.allowRelativeExternalFallthrough to true and remember to include external: ['external/y.js'] in the options you pass to rollup.rollup. If you forget that part, your build won't work, and weird things may happen instead!

options.leaveIdsAlone

When this is set to true, the IDs in import statements won't be treated as paths and will instead be looked up directly in the files object. There will be no relative importing, path normalization, or restrictions on the contents of IDs.

options.impliedExtensions

Set this to an array of file extensions to try appending to imports if an exact match isn't found. Defaults to ['.js', '/']. If this is set to false or an empty array, file extensions and trailing slashes in imports will be treated as mandatory.

options.cwd

When this is set to a directory name, relative file paths will be resolved relative to that directory rather than process.cwd(). When it's set to false, they will be resolved relative to an imaginary directory that cannot be expressed as an absolute path.

License

MIT