function Lifecycle()

in fusion-cli/build/dev-runtime.js [23:62]

• 37 lines of code
• 5 McCabe index (conditional complexity)

function Lifecycle() {
  const emitter = new EventEmitter();
  const state = {started: false, error: undefined};
  let listening = false;
  return {
    start: () => {
      state.started = true;
      state.error = undefined;
      emitter.emit('message');
    },
    stop: () => {
      state.started = false;
    },
    error: error => {
      state.error = error;
      // The error listener may emit before we call wait.
      // Make sure that we're listening before attempting to emit.
      if (listening) {
        emitter.emit('message', error);
      }
    },
    wait: () => {
      return new Promise((resolve, reject) => {
        if (state.started) resolve();
        else if (state.error) reject(state.error);
        else {
          listening = true;
          emitter.once('message', (error /*: Error */) => {
            if (error) {
              listening = false;
              return reject(error);
            }

            resolve();
          });
        }
      });
    },
  };
}