mmarchini

$ make LDFLAGS=-static NO_PERF_READ_VDSO32=1 NO_PERF_READ_VDSOX32=1 NO_JVMTI=1
  BUILD:   Doing 'make -j8' parallel build
  HOSTCC   fixdep.o
  HOSTLD   fixdep-in.o
  LINK     fixdep

Auto-detecting system features:
...                         dwarf: [ on  ]
...            dwarf_getlocations: [ on  ]
...                         glibc: [ on  ]

mmarchini

// Node v10.15.3
uprobe:/home/mmarchini/.nvm/versions/node/v10.15.3/bin/node:_ZN2v88internal17Builtin_JsonParseEiPPNS0_6ObjectEPNS0_7IsolateE
{
  // Load constants
  $kPointerSize = (uint32)(1 << (*uaddr("v8dbg_PointerSizeLog2")));
  $stringLengthOffset = (uint32)*uaddr("v8dbg_class_String__length__SMI");
  $kTag = (uint32)*uaddr("v8dbg_HeapObjectTag");
  $kTagMask = (uint32)*uaddr("v8dbg_SmiTagMask");
  $kShiftSize = (uint32)*uaddr("v8dbg_SmiShiftSize");

mmarchini

# Uncomment deb-src lines on /etc/apt/sources.list
sudo apt-get update

# Or replace ~/glibc with preferred path to store libc source
mkdir -p ~/glibc
cd ~/glibc

sudo apt-get install -y dpkg-dev
sudo apt-get build-deps libc6
apt-get source libc6

mmarchini

new Promise
console.log

mmarchini

Promise.reject(new Error());  // This will result in a rejection

new Promise((fulfill, reject) => {
  reject(new Error());  // This will result in a rejection
});

new Promise(() => {
  throw new Error();  // This will result in a rejection
});

mmarchini

// Callback version
const { readFile } = require('fs');

function readJsonFile(file, cb) {
  readFile(file, (err, data) => {
    if (err) {
      // If error while reading file, propagate the error via callback
      return cb(err, null);
    }
    // Unexpected invalid JSON input, code will throw

mmarchini

// async function version
const { readFile } = require('fs').promises;

async function readJsonFile(file) {
  // Promise is rejected if fails to read or if unexpected JSON input.
  return JSON.parse(await readFile(file));
}

mmarchini

async function foo() {
  throw new Error();
}

foo()  // 1. Unhandled at this point
  .catch(() => console.error("an error occured"));  // 2. Now it's handled

try {
  await foo();
} catch(e) {  // 3. Handled

mmarchini

const http = require('http');
const server = http.createServer(handle);

server.listen(3000);

function handle (req, res) {
  doStuff()
    .then((body) => {
      res.end(body);
    });

mmarchini

const http = require('http');
const server = http.createServer(handle);

server.listen(3000);

process.on('unhandledRejection', (err) => {
  throw err;
});

function handle (req, res) {