Get statistic about total count of ts files and files which is implemented by using Angular 2

angular2-stat.js

const fs = require("fs");
const path = require("path");
const walk = require("walk");

const PROJECT_PATH = path.resolve(path.dirname(__dirname), 'src'),
    checkRegExp = new RegExp("(^\\@[^@\\(]+\\()", "m"),
    filesCountToSkip = 0; // Some magic number of files which aren't related to the Angular at all

let totalTSFiles = 0,
    angular2TSFiles = 0;

const walker = walk.walk(PROJECT_PATH);

walker.on("file", (root, fileStats, next) => {
    const extension = fileStats.name.substr(-8);
    if (extension === ".spec.ts" || extension.substr(-5) === ".d.ts" || root.match(/helpers/) !== null || extension.substr(-3) !== ".ts") {
        next();
        return;
    }

    fs.readFile(root + "/" + fileStats.name, "utf-8", (err, contents) => {
        if (err) {
            throw err;
        }

        totalTSFiles++;
        if (checkRegExp.test(contents)) {
            angular2TSFiles++;
        }
    });

    next();
});

walker.on("end", () => {
    totalTSFiles -= filesCountToSkip;
    if (totalTSFiles < angular2TSFiles) {
        totalTSFiles = angular2TSFiles;
    }

    console.info(
        "total files:", totalTSFiles,
        "; Angular 2 files:", angular2TSFiles,
        "Percentage:", Math.round(angular2TSFiles / totalTSFiles * 1000) / 10 + '%'
    );
});