Gulpでjsonファイルをいい感じに読み込みたい

gulpfile.js

var gulp = require('gulp');
var pug = require('gulp-pug');
var data = require('gulp-data');
var fs = require('fs');

// hamlタスク設定
gulp.task('pug', function() {
	taskname = this.seq.slice(-1)[0]
	gulp.src(['./*/*.pug','./*.pug'],{base:'./'})
	.pipe(data(function(file){
		var dirname = "./json/";
		var files = fs.readdirSync(dirname);
		var json = {};
		files.forEach(function(filename){
			json[filename.replace(".json","")] = require(dirname + filename);
		});
		return {data:json};
	}))
	.pipe(pug({pretty: true}))
	.pipe(gulp.dest('./'));
});