例題分析
例題摘自:總結事件輪詢機制,以及宏任務隊列與微任務隊列
console.log('======== main task start ========');
new Promise(resolve => {
console.log('create micro task 1');
resolve();
}).then(() => {
console.log('micro task 1 callback');
setTimeout(() => {
console.log('macro task 3 callback');
}, 0);
})
console.log('create macro task 2');
setTimeout(() => {
console.log('macro task 2 callback');
new Promise(resolve => {
console.log('create micro task 3');
resolve();
}).then(() => {
console.log('micro task 3 callback');
})
console.log('create macro task 4');
setTimeout(() => {
console.log('macro task 4 callback');
}, 0);
}, 0);
new Promise(resolve => {
console.log('create micro task 2');
resolve();
}).then(() => {
console.log('micro task 2 callback');
})
console.log('======== main task end ========');