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/** example file
*
* this script tests async chain handling;
* runnig async functions sequentialy
* or running in parallel
*
*/
/**
* functions a and b are asyncohronus
*/
async function a(msg) {
sum = 0;
for (i=0 ; i< parseInt(Math.floor(Math.random() * 1000000000)); i++) {
sum += i;
}
console.log(msg, sum);
return sum
}
async function b(upto) {
sum = 0;
for (i=0 ; i< upto; i++) {
sum += i;
}
console.log(upto, sum);
return new Promise((resolve, reject) => { resolve(sum); });
}
/** test
* --- -- -- - - -
* is an asynchronous function
* that calls multiple times in parallel
* the a and b functions
*/
async function test() {
labels = ['one', 'two', 'three', 'four', 'five'];
labels.forEach( lab => {
a(lab)
});
console.log('test1');
limits = [1000000, 50000, 30000000, 500, 8];
limits.forEach( lim => {
b(lim).then(console.log(lim,'is done!'));
});
console.log('test2');
}
test() // run test (many async functions in parallel)
.then(() => { // after test is ended
console.log('test parts(1+2) ended');
// run async functions in sequentialy
a('more')
.then(() => {
b(100000)
.then(() => {
a('last')
.then(() => {
b(20)
.then(() =>{
console.log('exiting...');
console.log('\n\n--------------------\nNext please...\n--------------------\n\n');
})
});
});
});
});
/**
* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
* -----------------------------------------------------------------------------
*
* * * * * * * * * * * * S E C O N D E X A M P L E * * * * * * * * * * * *
*
* -----------------------------------------------------------------------------
* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
*/
/** sleep
* --- -- -- - - -
* an async function with predictable waiting time
*/
async function sleep(time = 1) {
const sleepMilliseconds = time * 1000;
return new Promise((resolve, reject) => {
setTimeout(() => {
console.log(`Slept for: ${sleepMilliseconds}ms`);
resolve(sleepMilliseconds);
}, sleepMilliseconds);
});
}
// run all in parallel
Promise.all([ // after each call is completed
// '.then(...)' make a message note
sleep(3).then(()=>{ console.log('instance', 3, 'completed')}),
sleep(2).then(()=>{ console.log('instance', 2, 'completed')}),
sleep(1).then(()=>{ console.log('instance', 1, 'completed')})
])
.then( () => { // then
console.log('Now, there should be all done!', 'DONE!')
});
// message to test that async functions keep running on the background
console.log('--> is this the end?', 'NOPE! <--');
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