Runtime
A plugin type: Programmatically insert assets out of thin air into bundles
 The Runtime API is experimental and therefore subject to change, even between minor updates. 
Runtimes accept a bundle and return assets to be inserted into that bundle.
import { Runtime } from "@parcel/plugin";
export default new Runtime({
  async apply({ bundle, bundleGraph }) {
    // ...
    return assets;
  },
}); Relevant API
#RuntimeAsset parcel/packages/core/types/index.js:1555
A "synthetic" asset that will be inserted into the bundle graph.
type RuntimeAssetΒ = {|   +filePath: FilePath,   +code: string,   +dependency?: Dependency,   +isEntry?: boolean,   +env?: EnvironmentOptions, |} Referenced by:
RuntimeRuntime parcel/packages/core/types/index.js:1566
type Runtime<ConfigType>Β = {|   loadConfig?: ({|
    config: Config,
    options: PluginOptions,
    logger: PluginLogger,
  |}) => Promise<ConfigType> | ConfigType,   apply({|
    bundle: NamedBundle,
    bundleGraph: BundleGraph<NamedBundle>,
    config: ConfigType,
    options: PluginOptions,
    logger: PluginLogger,
  |}): Async<void | RuntimeAsset | Array<RuntimeAsset>>, |}