Javascript loop through array asynchronous

user_8273121 0
Viewed 3697

I'm making a bot code for a game running on NodeJS and what this function is supposed to do is to loop through an array of vectors and then make the bot go to each vector.

However, what it's actually doing is telling the bot to run to all the vectors at the same time so it spazzes out and then runs to the last vector in the array:

function digSchedule() {
    var arrayLength = blocksToMine.length;
    for (var i = 0; i < blocksToMine.length; i++) {
        console.log(i);
        scaffoldTo(blocksToMine[i]);
    }
    ...
}

The function scaffoldTo() needs to be ran and then wait for the bot to do said function then run it for the next element in the array, but I can't figure out how to do it.

asynchronous arrays loops javascript
5 Answers

You may use async module to achieve this. Alternatively, you may try something like this

function forEachAsync(array, fun, cb) {
        var index = 0;
        if (index == array.length) {
                cb(null);
                return;
        }

        var next = function () {
                fun(array[index], function(err) {
                        if (err) {
                                cb(err);
                                return;
                        }
                        index++;
                        if (index < array.length) {
                                setImmediate(next);
                                return;
                        }

                        //We are done
                        cb(null);
                });
        };

        next();
}

forEachAsync([1,2,3,4,5], function(e, cb) {
        console.log(e);
        cb();
}, function(err) {
        console.log('done');
});
user_108820570

Here is how we do with the help of promises.

let numbers = new Array(1,3,2,1);
function asyncFunction(number){
    return new Promise((resolve,reject)=>{
        setTimeout(()=>{
            console.log("Number : ",number);
            return resolve();
        },number*1000);
    })
  
}
let promise = Promise.resolve();
// Here we are using forEach to chain promise one after another.
numbers.forEach(number=>{
    promise = promise.then(()=>{
        return asyncFunction(number);
    });
})
promise.then(()=>{
    console.log("Every thing is done!");
})
user_75567240
Related