Function perEnvironmentState

packages/vite/src/node/environment.ts:20–31

(
  initial: (environment: Environment) => State,
)

 * @experimental
 */
export function perEnvironmentState<State>(
  initial: (environment: Environment) => State,
): (context: PluginContext) => State {
  const stateMap = new WeakMap<Environment, State>()
  return function (context: PluginContext) {
    const { environment } = context
    if (!stateMap.has(environment)) {
      stateMap.set(environment, initial(environment))
    }
    return stateMap.get(environment)!
  }
}