I want to use the JavaScript .apply method to functions of a thrift piled for Node.js. The thrift .js file has code like this:

...
var NimbusClient = exports.Client = function(output, pClass) {
    this.output = output;
    this.pClass = pClass;
    this.seqid = 0;
    this._reqs = {};
};
NimbusClient.prototype = {};
NimbusClient.prototype.getClusterInfo = function(callback) {
    this.seqid += 1; // line where error is thrown [0]
    this._reqs[this.seqid] = callback;
    this.send_getClusterInfo();
};
...

My server file looks the following way:

var thrift = require('thrift')
    , nimbus = require('./Nimbus')
    , connection = thrift.createConnection('127.0.0.1', 6627)
    , client = thrift.createClient(nimbus, connection)
    , ... // server initiation etc

app.get('/nimbus/:mand', function(req, res, next) {
    client[req.paramsmand](console.log); // direct call [1]
    client[req.paramsmand].apply(this, [console.log]); // apply call [2]
});

...

The direct call [1] returns the values as expected, but the apply call [2] always produces the following error in line [0]:

TypeError: Cannot set property 'NaN' of undefined

I tried several other scope parameters in [2]: null, nimbus, nimbus.Client, nimbus.Client.prototype, nimbus.Client.prototype[req.paramsmand] and client[req.paramsmand], all without success.

How can I call the apply method without changing the actual scope of the function called, so that it behaves exactly the same as it would if called in the direct way?

I want to use the JavaScript .apply method to functions of a thrift piled for Node.js. The thrift .js file has code like this:

...
var NimbusClient = exports.Client = function(output, pClass) {
    this.output = output;
    this.pClass = pClass;
    this.seqid = 0;
    this._reqs = {};
};
NimbusClient.prototype = {};
NimbusClient.prototype.getClusterInfo = function(callback) {
    this.seqid += 1; // line where error is thrown [0]
    this._reqs[this.seqid] = callback;
    this.send_getClusterInfo();
};
...

My server file looks the following way:

var thrift = require('thrift')
    , nimbus = require('./Nimbus')
    , connection = thrift.createConnection('127.0.0.1', 6627)
    , client = thrift.createClient(nimbus, connection)
    , ... // server initiation etc

app.get('/nimbus/:mand', function(req, res, next) {
    client[req.params.mand](console.log); // direct call [1]
    client[req.params.mand].apply(this, [console.log]); // apply call [2]
});

...

The direct call [1] returns the values as expected, but the apply call [2] always produces the following error in line [0]:

TypeError: Cannot set property 'NaN' of undefined

I tried several other scope parameters in [2]: null, nimbus, nimbus.Client, nimbus.Client.prototype, nimbus.Client.prototype[req.params.mand] and client[req.params.mand], all without success.

How can I call the apply method without changing the actual scope of the function called, so that it behaves exactly the same as it would if called in the direct way?

• javascript
• node.js
• scope

• foo.apply(null,…) produces the same error – Thomas Commented Dec 5, 2012 at 18:30
• I'm kind of curious as to why you want to use the apply method in the first place if you wish to retain the default scope... – subhaze Commented Dec 5, 2012 at 18:31
• @subhaze: I boiled it down for this example. I need the number of arguments to be variable, because most Nimbus functions expect more than just the callback as parameters. – Thomas Commented Dec 5, 2012 at 18:33
• 2 Ahh, ok. Have you tried client[req.params.mand].apply(client, [console.log]); by chance? – subhaze Commented Dec 5, 2012 at 18:34
• 1 this may be related stackoverflow./questions/11536177/… – lostsource Commented Dec 5, 2012 at 18:42

1 Answer 1

Pointing the apply function back to the same function like this should retain the original scope.

client[req.params.mand].apply(client, [console.log]);