[Solved] Help with the order of execution: async.each in an async.waterfall

[navid.sassan]

Hello,

I am trying to use an async.each during an asyc.waterfall in a NodeBB plugin, however the order of execution is not what I expect.

Code:

async.waterfall([
    function(next) {
        Groups.getGroupsFromSet('groups:createtime', 0, 0, -1, next);
    },
    function(groups, next) {
        // log(`groups: ${groups}`)
        // log(`groups: ${groups[0].name}`)
        next(err, groups)
    },
    function(groups, next) {
        async.each(groups, function(element, eachCallback) {
            if (!element.name.match('privileges')) {
                Groups.ownership.isOwner(uid, element.name, function(err, isOwnerBool) {
                    if (isOwnerBool) {
                        renderData.groups.push(element)
                        log(`element.name: ${element.name}`)
                    }
                })
            }
            eachCallback(err)
        },
        function(err) {
            if (err) {
                log(`ERROR in async.each! ${err}`);
            } else {
                log('No error happened in any steps, next()!');
            }
            next(err)
        })
    },
    function(next) {
        log('I got called!')
        log(`renderData.groups: ${renderData.groups}`)
        next(err)
    }
],
function(err) {
    if (err) {
        log(`ERROR! ${err}`);
    } else {
        log('No error happened in any steps, operation done!');
    }
});

Actual output:

No error happened in any steps, next()!
I got called!
renderData.groups:
No error happened in any steps, operation done!
element.name: My Group A
element.name: My Group B

Expected output:

element.name: My Group A
element.name: My Group B
No error happened in any steps, next()!
I got called!
renderData.groups: [object Object],[object Object]
No error happened in any steps, operation done!

Any help is appreciated, thank you

Edit: Adjusted expected output, sorry for the confusion.

[PitaJ]

You need to call eachCallback within the callback you pass to Groups.ownership.isOwner. In the case you have a privilege group, you can just exit early like so:

// not exactly what you want, just an example
if (condition) {
  callback();
  return;
}

// then do other stuff

[navid.sassan]

Do you mean this?

async.waterfall([
    function(next) {
        Groups.getGroupsFromSet('groups:createtime', 0, 0, -1, next);
    },
    function(groups, next) {
        // log(`groups: ${groups}`)
        // log(`groups: ${groups[0].name}`)
        next(err, groups)
    },
    function(groups, next) {
        async.each(groups, function(element, eachCallback) {
            if (!element.name.match('privileges')) {
                Groups.ownership.isOwner(uid, element.name, function(err, isOwnerBool) {
                    if (isOwnerBool) {
                        renderData.groups.push(element)
                        log(`element.name: ${element.name}`)
                    }
                    eachCallback(err)
                })
            }
        },
        function(err) {
            if (err) {
                log(`ERROR in async.each! ${err}`);
            } else {
                log('No error happened in any steps, next()!');
            }
            next(err)
        })
    },
    function(next) {
        log('I got called!')
        log(`renderData.groups: ${renderData.groups}`)
        next(err)
    }
],
function(err) {
    if (err) {
        log(`ERROR! ${err}`);
    } else {
        log('No error happened in any steps, operation done!');
    }
});

This leads to the following output:

element.name: My Group A
element.name: My Group B

For context, I am trying to get a list of all groups, of which the current user is the owner.Therefore I also do not want to exit the async.each on the first privilege group, but find them all and add them to the renderData.groups array.

[PitaJ]

@navid-sassan you need to call eachCallback no matter what, otherwise it will hang.

async.each(groups, function(element, eachCallback) { 
  if (element.name.match('privileges')) {
    eachCallback();
    return; // only exits this callback function, skips the ownership check
  }
  Groups.ownership.isOwner(uid, element.name, function(err, isOwnerBool) {
    if (isOwnerBool) {
      renderData.groups.push(element) 
      log(`element.name: ${element.name}`)
    }
    eachCallback(err)
  }),
}

[PitaJ]

Just FYI, pretty sure you can use async.filter for this.

[navid.sassan]

Thank you very much! The code worked, and I will look into async.filter, it looks promising, thanks for the hint