client.js

import { getHooksAfter, getHooksBefore } from './common';
import MethodInvoker from 'meteor/ddp-client/common/MethodInvoker.js';

const originalSend = MethodInvoker.prototype.sendMessage;
const originalReceive = MethodInvoker.prototype.receiveResult;

MethodInvoker.prototype.sendMessage = function sendMessage() {
  if (this._message.msg === 'method') {
    const beforeFns = getHooksBefore(this._message.method);
    for (const beforeFn of beforeFns) {
      if (beforeFn.apply(this, this._message.params) === false) {
        return false;
      }
    }
  }

  return originalSend.call(this);
};

MethodInvoker.prototype.receiveResult = function receiveResult(error, result) {
  const context = {
    error,
    result,
  };

  if (!this.gotResult()) {
    const afterFns = getHooksAfter(this._message.method);
    for (const afterFn of afterFns) {
      try { afterFn.apply(context, this._message.params); } catch (err) {
        console.error(err);
      }
    }
  }

  originalReceive.call(this, context.error, context.result);
};