Generated by XState Viz: https://xstate.js.org/viz

machine.js

const validate = async () => null;

// validation helpers ------------------------------------------------------ //

const should_validate = (context) => {
  return (context.value &&
    ((context.leaving && context.validate) ||
    (!context.leaving && context.validated))
  )
};

const check = async (context) => {
  if (should_validate(context)) {
    let validated = true;
    let valid = true;
    let errors = null;
    let result = await validate(context.value, context.validators);
    
    if (result && result.length > 0) {
      errors = result;
      valid = false;
    }

    return { valid, validated, errors };
  }

  return {};
};

// machine actions --------------------------------------------------- //

const update_value = assign({ value: (context, event) => event.data  });

const update_validation_results = assign((context, event) => event.data);

const set_leaving = assign({ leaving: true });

const unset_leaving = assign({ leaving: false });

// machine parts ----------------------------------------------------- //

const validatable = {
  id: 'validatable',
  initial: 'checking',
  states: {
    checking: {
      invoke: {
        src: 'check',
        onDone: {
          actions: ['update_validation_results'],
          target: 'selection',
        },
      },
    },
    selection: {
      on: {
        '': [{
          target: '#input.idle',
          cond: 'should_leave',
        },
        {
          target: 'invalid',
          cond: 'is_invalid',
        },
        {
          target: 'valid',
          cond: 'is_valid',
        }],
      }
    },
    invalid: {
      on: {
        change: {
          actions: ['update_value'],
          target: 'checking',
        },
        blur: {
          actions: ['set_leaving'],
          target: 'checking',
        },
      },
    },
    valid: {
      on: {
        change: {
          actions: ['update_value'],
          target: 'checking',
        },
        blur: {
          actions: ['set_leaving'],
          target: 'checking',
        },
      },
    },
  },
};

const fillable = {
  id: 'fillable',
  initial: 'empty',
  states: {
    empty: {
      always: {
        target: 'filled',
        cond: 'has_value',
      },
      on: {
        change: {
          target: 'filled',
        },
      },
    },
    filled: {
      on: {
        change: {
          target: 'empty',
          cond: 'is_empty',
        },
      },
      ...validatable,
    },
    hist: {
      type: 'history',
      history: 'deep',
      target: 'empty',
    },
  },
};

const input_machine = Machine(
  {
    id: 'input',
    initial: 'idle',
    context: {
      value: null,
      valid: true,
      validate: false,
      validated: false,
      validators: {},
      errors: null,
      options: {
        id: null,
        name: null,
        label: null,
        field_type: null,
        disabled: false,
        required: false,
      },
      // utility states for the machine
      leaving: false,
    },
    states: {
      idle: {
        on: {
          focus: {
            actions: ['unset_leaving'],
            target: 'focused.hist'
          },
        },
      },
      focused: {
        ...fillable,
      },
    },
  },
  {
    actions: {
      update_value,
      update_validation_results,
      set_leaving,
      unset_leaving,
    },
    guards: {
      is_empty: context => context.value === null,
      has_value: context => context.value !== null,
      is_valid: context => context.valid === true && context.errors === null,
      is_invalid: context => context.valid === false || !context.errors !== null,
      should_leave: context => context.leaving === true,
    },
    services: {
      check,
    }
  }
);