embedding js implementation

// dash.ts: https://github.com/y21/dash/blob/master/wasm/frontend/dash.ts
import { Engine } from './dash';

const commands = new discord.command.CommandGroup({
  defaultPrefix: '..'
});

function removeCodeblock(code: string): string {
  return code.replace(/^```\w*|```$/g, '');
}

function codeblock(language: string, code: string) {
  return '```' + language + '\n' + code.substr(0, 1900) + '\n```';
}

const engine = new Engine();
const WASM_URL = 'http://dash.y21_.repl.co/wasm/v3';

discord.on(discord.Event.MESSAGE_CREATE, async (message) => {
  // initialize js engine if it's not yet ready
  if (!engine.initialized) {
    await engine.init(WASM_URL);
  }
});

async function handleEval(
  message: discord.GuildMemberMessage,
  { code }: { code: string }
) {
  code = removeCodeblock(code);
  let result;

  let before = await pylon.getCpuTime();
  try {
    result = engine.eval(code);
  } catch (e) {
    result = e.message;
  }
  let now = await pylon.getCpuTime();

  message.reply({
    content: (now - before).toFixed(2) + ' ms' + codeblock('js', result),
    allowedMentions: {}
  });
}

const dashGroup = commands.subcommandGroup({
  name: 'eval2'
});

dashGroup.default(
  (args) => ({
    code: args.text()
  }),
  handleEval
);

dashGroup.on(
  'run',
  (args) => ({
    code: args.text()
  }),
  handleEval
);