Node.js - error

Node.js的错误有以下几种：

• 标准 JavaScript 错误，比如eval error、syntax error、range error、reference error、type error、uri error
• 系统错误
• 用户指定错误
• 断言错误

try {
  const a = 1
  const c = a + b
} catch (err) {
  console.log(err)
}

以上代码输出ReferenceError:b is not defined

const fs = require('fs')
function nodeStyleCallback(err, data) {
  if (err) {
    console.error('There was an error', err)
    return
  }
  console.log(data)
}
fs.readFile('/some/file/that/does-not-exist', nodeStyleCallback)
fs.readFile('/some/file/that/does-exist', nodeStyleCallback)