Node Event Loop

下面两段代码，你能说出正确的打印顺序分别是什么吗？

setTimeout(() => {
  console.log('timeout');
}, 0);

setImmediate(() => {
  console.log('immediate');
});

// 无法确定打印顺序

const fs = require('fs');

fs.readFile(__filename, () => {
  setTimeout(() => {
    console.log('timeout');
  }, 0);
  setImmediate(() => {
    console.log('immediate');
  });
});

// 先 immediate
// 后 timeout

不是我懒惰，是我怕翻译错
so
Node 官方解读在这里

下面是写的比较好的博客，它们是一个系列哦：

• Event Loop and the Big Picture — NodeJS Event Loop Part 1
• Timers, Immediates and Process.nextTick — NodeJS Event Loop Part 2
• Promises, Next-Ticks, and Immediates — NodeJS Event Loop Part 3
• Handling IO — NodeJS Event Loop Part 4
• New Changes to the Timers and Microtasks in Node v11.0.0 (and above)
• Event Loop Best Practices — NodeJS Event Loop Part 5