Problem with forEach if iterator-function is prototype-function and uses "this"

[jochenonline]

I am having problems using forEach if the iterator-function (2nd argument) is a prototype-function of an obejct and uses "this" within its function-body.

Concrete: I am trying to use forEach with "client.add" of node-solr (https://github.com/gsf/node-solr/blob/master/lib/solr.js - line 77).

When I use the following code:

async.forEachSeries( doc_arr, client.add, function(err) {
    if( err ) { 
         throw err; 
    }
});

I get: 'this' has no function 'update'. Which is in line 109 of the mentioned solr.js.

What can I do?

[fent]

This is how javascript works. If you give a function, it can get called within a different context.

You can specify the context with the Function#bind() method.

client.add.bind(client)

[jochenonline]

..and this is how learning JS works: everyday something new. Thanks! It works!!!