编辑代码

console.log('start');

setTimeout(() => {
    console.log('timeout');
    process.nextTick(() => {
        console.log('nextTick');
    });
}, 1000);

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

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

process.nextTick(() => {
    console.log('nextTick1');
});

console.log('end');