Parallel synchronous functions with a common resolve in Node.js

parallelSync.js

function parallelSync(arrOfSyncFunctions){
    return new Promise(async resolve =>{
        let numToResolve = arrOfSyncFunctions.length;
        let numResolved = 0;
        // call after each async function resolves
        const resolveOne = () =>{
            numResolved++;
            if(numResolved >= numToResolve){
                // all functions have resolved. Resolve finally
                resolve();
            }
        };
        // call all sync functions in parallel
        for(let i = 0; i < numToResolve; i++){
            (async (i)=>{
                await arrOfSyncFunctions[i]();
                resolveOne();
            })(i)
        }
    });
}

(async ()=>{
    // run syncronus tasks in parallel and wait for all of them to resolve
    // each array function will run asynchronusly but will con continue until all are resolved
    // you can put as many in the array as you need.
    await parallelSync([
        async ()=>{
            await someSynchronusTask();
            await someSynchronusTask2();
        },
        async ()=>{
            await someSynchronusTask3();
            await someSynchronusTask4();
        }
    ]);
    console.log('parallel sync complete')
})()