API state machine part 1

ApiStateMachinePart1.js

class ApiStateMachine {
  state = {
    current: 'idle',
  };
  next(input) {
    let nextState;
    switch (this.state.current) {
      case 'idle': nextState = 'pending'; break;
      case 'pending': nextState = input ? 'success' : 'error'; break;
      default: nextState = 'idle';
    }
    this.state.current = nextState;
}