Not working with Grunt about epub-gen HOT 6 CLOSED

@timtribers

Hope that helps someone.

You're damn right it did. If you were standing here, I'd kiss you.

This is also relevant:

gruntjs/grunt#1531 (comment)

You cannot use this.async() this if you use the fancy "fat arrow" syntax:

grunt.registerTask('build', 'Make the EPUB', () => { ... }

You have to do the old school syntax:

grunt.registerTask('build', 'Make the EPUB', function() { ... }

from epub-gen.

Hi, @timtribers
Could you provide the script or configuration you run with grunt?
Thanks.

from epub-gen.

Hi @cyrilis

Actually, think I might just have worked out the problem . . .

Grunt tasks are synchronous by default, so wrapping epub-gen is fine, up until it hits some async stuff such as using fs to write a file.

There is a way to flag to make a Grunt task async - will try that.

Thx

from epub-gen.

@timtribers
You can try:

    new Epub(option [, output]).promise.then(function(){
        console.log("Ebook Generated Successfully!")
    }, function(err){
        console.error("Failed to generate Ebook because of ", err)
    })

for asynchronous usage.

cheers.

from epub-gen.

Yay, that was the problem - should have guessed sooner.

Here's how to wrap in Grunt, for anyone coming to this in the future . . .

  // Custom task to write epub file
  grunt.registerTask('epubGen', function(){
    var done = this.async();
    var Epub = require("epub-gen");
    ...
    new Epub(option [, output]).promise.then(function(){
        console.log("Ebook Generated Successfully!")
        setTimeout(function(){done();}, 1000);
    }, function(err){
        console.error("Failed to generate Ebook because of ", err)
        done(err);
    });
   });

Sorry to have raised an issue.

Thx for a great library.

from epub-gen.

Postscript
After using the above for around a month, I was still getting random times when the produced epub file was corrupted and unreadable. I spent a frustrating day trying to debug the problem, and eventually concluded that it was another timing issue.

It's crude, but the only way I found to make it go away altogether was to amend the code immediately above to replace:
done();
with:
setTimeout(function(){done();}, 1000);

Hope that helps someone.

from epub-gen.