html_task.js

var gulp            = require('gulp'),
    flatten         = require('gulp-flatten');

// Estrutura da pasta
const srcPaths = {
  html: 'src/pug/**/*.pug',
  exclude: '!src/pug/layouts/inc/*.pug'
};

const buildPaths = {
  html: './build/',
};

gulp.task('default', ['html','w']);

// Task
gulp.task('html', () => {
  gulp.src([
    srcPaths.html,
    srcPaths.exclude
  ])
    //.pipe(plumber())
    .pipe(pug({
      pretty: true
    }))
    .on('error', onError)
    .pipe(flatten())
    .pipe(
      gulp.dest(
        buildPaths.html
      )
    );
});

// WATCH
gulp.task('w',['html'], function() {
    gulp.watch(srcPaths.html,    ['html']);
});