Issue with Bluebird.promisify()

[cvburgess]

Howdy!

Tried promisifying the sendEmailBatch function and it gave me a peculiar error...

I tried using the callback style and it works, but promises are a must-have in my current project.

Here's the code:

const Promise = require('bluebird');
const postmark = require('postmark');

const client = new postmark.Client(<api_key>);

const messages = []; // array or message objects
const sendEmails = Promise.promisify(client.sendEmailBatch);

return sendEmails(messages);

Unhandled rejection TypeError: this.processRequestWithBody is not a function
at Client.sendEmailBatch (/<project path>/node_modules/postmark/lib/postmark/Client.js:120:14)

[cvburgess]

As a workaround for now, I am using this hack:

return new Promise((resolve, reject) => {

  client.sendEmailBatch(messages, (error, success) => {

    if (error) reject(error);

    resolve(success);

  });

});

[mansona]

Hey @cvburgess I have implemented something very similar using a corresponding function on q.js

Essentially Q has two functions for wrapping node style functions: Q.denodeify and Q.nbind

Denodeify should be used for static functions and nbind should be used for functions that are part of an object and make use of this. In this case, you have to use Q.nbind with postmark.sendEmail because it is part of the postmark object.

Here is my code:

const postmark = require('postmark');
const Q = require('q');

const client = new postmark.Client(nconf.get('postmark:api_key'));
const sendEmail = Q.nbind(client.sendEmail, client);

Obviously, this doesn't directly apply to you but you will need to find the corresponding function to Q.nbind in Bluebird.

[atheken]

Hey folks, I just want to acknowledge this issue. I'll have a look at the code and see if it's an issue related to the prototype for Client.

[sudo-suhas]

I was able to work with bluebird by doing the following:

const Promise = require('bluebird'), // eslint-disable-line no-shadow
    postmark = require('postmark');

const client = new postmark.Client(postmarkConfig.apiToken),
    sendEmailWithTemplate = Promise.promisify(client.sendEmailWithTemplate, {context: client});

// Usage
// Returns a promise
sendEmailWithTemplate({
    From: from,
    To: to,
    TemplateId: postmarkConfig.templates[type],
    TemplateModel: locals
});

[stringbeans]

as an FYI, this is not an issue with postmark.js but an issue with how you're using Promise.promisify. You must bind the correct context to the function you are "promisifying"

[cvburgess]

I will try this in my code and close this issue if it works - thanks @stringbeans :)

[atheken]

We just released 1.4.0 of the library, which includes Promise support. To get Promises back, simply call the same client methods without a callback function. The client methods will return a Promise when the callback function is emitted.

[cvburgess]

Thank you @atheken I will update tonight :D