While the technique in the accepted answer can solve your issue, it’s an anti-pattern. Resolving a promise with an error isn’t good practice and there is a cleaner way of doing this.
What you want to do, in pseudo-code, is:
fn task() {
result-1 = doAsync();
result-n = doAsync();
// handle results together
return handleResults(result-1, ..., result-n)
}
This can be achieved simply with async/await without the need to use Promise.all. A working example:
console.clear();
function wait(ms, data) {
return new Promise( resolve => setTimeout(resolve.bind(this, data), ms) );
}
/**
* These will be run in series, because we call
* a function and immediately wait for each result,
* so this will finish in 1s.
*/
async function series() {
return {
result1: await wait(500, 'seriesTask1'),
result2: await wait(500, 'seriesTask2'),
}
}
/**
* While here we call the functions first,
* then wait for the result later, so
* this will finish in 500ms.
*/
async function parallel() {
const task1 = wait(500, 'parallelTask1');
const task2 = wait(500, 'parallelTask2');
return {
result1: await task1,
result2: await task2,
}
}
async function taskRunner(fn, label) {
const startTime = performance.now();
console.log(`Task ${label} starting...`);
let result = await fn();
console.log(`Task ${label} finished in ${ Number.parseInt(performance.now() - startTime) } miliseconds with,`, result);
}
void taskRunner(series, 'series');
void taskRunner(parallel, 'parallel');Note: You will need a browser which has async/await enabled to run this snippet.
This way you can use simply try/ catch to handle your errors, and return partial results inside parallel function.