new Promise((resolve, reject) => {
console.log("promise1")
resolve()
}).then(() => {
console.log("then11")
new Promise((resolve, reject) => {
console.log("promise2")
resolve()
}).then(() => {
console.log("then21")
}).then(() => {
console.log("then23")
})
}).then(() => {
console.log("then12")
})The above code output is following, When I test my understanding of micro task and macro task with promise and I can not get the correct output.
// "promise1"
// "then11"
// "promise2"
// "then21"
// "then12"
// "then23"
To be more specific, I am confused about the last 3 outputs. Thanks for the help!
// "then21"
// "then12"
// "then23"
If you're looking for this output:
// "promise1"
// "then11"
// "promise2"
// "then21"
// "then23"
// "then12"
Then return the Promise inside your first .then(, like this:
new Promise((resolve, reject) => {
console.log("promise1")
resolve()
}).then(() => {
console.log("then11")
return new Promise((resolve, reject) => {
console.log("promise2")
resolve()
}).then(() => {
console.log("then21")
}).then(() => {
console.log("then23")
})
}).then(() => {
console.log("then12")
})The return returns the Promise made by the last .then( in the chain after your second new Promise. Your very last .then( will await the then23 .then(, then execute.