grunt is not defined default not found - gruntjs

Question

I want to create yoeman generator for html template project
when i try to launch grunt i ha this error Task 'default not found
grunt build give grunt is not defined
$> grunt
Loading "Gruntfile.js" tasks...ERROR
>> ReferenceError: grunt is not defined
Warning: Task "default" not found. Use --force to continue.
Aborted due to warnings.
Here is my code
var fs = require('fs');
var path = require('path');
var showdown = require('showdown');
var EJS = require('ejs');
var TemplateRender = function(file, destination, source, template) {
this.file = file;
this.destination = destination;
this.source = source;
this.template = template;
this.grunt = grunt;
};
TemplateRender.prototype = {
render: function() {
var file = this._read();
var html = this._convert(file);
var content = this._template(html);
this._write(content);
},
_read: function() {
var filepath = path.join(this.source,this.file);
grunt.file.read(filepath);
},
_convert: function(file) {
return new showdown.convertor().makeHtml(file);
},
_template: function(html) {
var template = this.grunt.file.read(this.template);
return EJS.render(template,{content:html});
},
_write: function() {
this.grunt.file.write(
path.join(this.destination, this.file),
page
);
}
};
'use strict';
module.exports = function(grunt) {
grunt.registerTask('build', function() {
var template = "app/index.ejs",
destination = path.join(process.cwd(),"dist"),
source = path.join(process.cwd(),"posts"),
files = fs.readdirSync(source);
files.forEach(function(file) {
new TemplateRender(file, destination, source, template, grunt).render();
read();
convert();
template();
write();
});
});
};
I need to know how to detect error in grunt and yeoman

Answer 1

At the top of your code, in the TemplateRender function, you have this line: this.grunt = grunt; But you don't actually have an argument by that name. Try this:
// ... (everything the same above here)
// *** Notice the new argument to this constructor function
var TemplateRender = function(file, destination, source, template, grunt) {
this.file = file;
this.destination = destination;
this.source = source;
this.template = template;
this.grunt = grunt;
};
TemplateRender.prototype = {
// ...
_read: function() {
var filepath = path.join(this.source,this.file);
// *** probably needs to be `this.grunt` ?
this.grunt.file.read(filepath);
},
// ...
};
module.exports = function(grunt) {
grunt.registerTask('build', function() {
// ... (mostly the same)
files.forEach(function(file) {
new TemplateRender(file, destination, source, template, grunt).render();
// *** where are these defined? Should they be: this._read(), etc?
this._read();
this._convert();
this._template();
this._write();
});
});
};