outline/server/api/middlewares/apiWrapper.js

// @flow
import { type Context } from 'koa';

export default function apiWrapper() {
  return async function apiWrapperMiddleware(
    ctx: Context,
    next: () => Promise<void>
  ) {
    await next();

    const ok = ctx.status < 400;

    // $FlowFixMe
    ctx.body = {
      ...ctx.body,
      status: ctx.status,
      ok,
    };
  };
}