function delay(n) {
return new Promise(resolve => setTimeout(resolve, n))
}the return statement in this function is a little difficult to understand.
resolve => setTimeout(resolve, n)
= > is this an arrow function?
if yes, resolve is the parameter of setTimeout,
delay function takes an argument n, and this setTimeout function introduces a new parameter.
it"s a little confusing. Please explain.
https://developer.mozilla.org.
suggests viewing Promise documents
the complete state is as follows: there is a setTimeout in the arrow function let delay = n = > new Promise (resolve = > setTimeout (resolve,n));
promise ) is the first parameter of the callback function resolve is to change the state to success
setTimeout the first argument is the callback function's second parameter is the delay time setTimeout (resolve,n) is n millisecond later call resolve < /
function delay(time) {
return new Promise(function(resolve){
setTimeout(resolve, time)
})
}
delay(3000) //3promise
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