How to use the fs.readFileSync function in fs

function _parseCommandLineOptions(options) {
    for (var i = 0, iz = argv.length; i < iz; ++i) {
        switch (argv[i]) {
        case "-h":
        case "--help":      options.help = true; break;
        case "-v":
        case "--verbose":   options.verbose = true; break;
        case "--nowrap":    options.nowrap = true; break;
        case "--header":    options.header = fs.readFileSync(argv[++i], "utf8"); break;
        case "--footer":    options.footer = fs.readFileSync(argv[++i], "utf8"); break;
        case "--es5in":     options.es5in = true; break;
        case "--es6in":     options.es6in = true; break;
        case "--es5out":    options.es5out = true; break;
        case "--es6out":    options.es6out = true; break;
        case "--strict":    break; // [DEPRECATED]
        case "--keep":      options.keep = true; break;
        case "--simple":    break; // [DEPRECATED]
        case "--extern":
        case "--externs":   _pushif(options.externs, argv[++i]); break;
        case "--option":    _pushif(options.option, argv[++i]); break;
        case "--pretty":    options.pretty = true; break;
        case "--optimize":  _pushif(options.externs, argv[++i]); break;
        case "--concat":    options.optimize = 0;
                            options.include_modules = true; break;
        case "--debug":     options.optimize = 1;

const path = `node_modules/${packageName}/${name}.js`
  const data = readFileSync(path, 'utf8')

  writeFileSync(path, data.replace(src, dest))
}

// Fix versions in `react-native-sensitive-info` directly

const path_csproj = `node_modules/react-native-sensitive-info/windows/RNSensitiveInfo/RNSensitiveInfo/RNSensitiveInfo.csproj`
const data_csproj = readFileSync(path_csproj, 'utf8')

writeFileSync(path_csproj, data_csproj.replace('10.0.10586.0', '10.0.14393.0'))

const path_project = `node_modules/react-native-sensitive-info/windows/RNSensitiveInfo/RNSensitiveInfo/project.json`
const path_projectlock = `node_modules/react-native-sensitive-info/windows/RNSensitiveInfo/RNSensitiveInfo/project.lock.json`
const data_project = readFileSync(path_project, 'utf8')

writeFileSync(path_project, data_project.replace('"Microsoft.NETCore.UniversalWindowsPlatform": "5.2.2",', '"Microsoft.NETCore.UniversalWindowsPlatform": "6.0.6",').replace("uap10.0","uap10.0.14393"))
unlinkSync(path_projectlock)

// Replace usage of `react-native-web` for `react-native-web_improved`
replace.call({
  dest: 'react-native-web_improved',
  packageName: 'babel-plugin-react-native-web',
  src: 'react-native-web'
}, 'index')

const performBabelRequire = (filename: string) => {
  workingParentFile = filename;
  const { code } = require('@babel/core').transform(readFileSync(filename).toString(), {
    filename,
    ...(getBabelPresetsAndPlugins()),
  });
  return requireFromString(code, filename);
  // return requireFromString(code);
};

var Fhir = require('../fhir').Fhir;
var FhirPath = require('../fhirPath').FhirPath;
var fs = require('fs');
var assert = require('assert');
var _ = require('underscore');

var documentBundleJson = fs.readFileSync('./test/data/stu3/document-example-dischargesummary.json').toString();
var questionnaireResponseJson = fs.readFileSync('./test/data/r4/QuestionnaireResponse_01.json').toString();

describe('FhirPath', function() {
    var resource = JSON.parse(documentBundleJson);

    describe('parse', function() {
        var fhirPath = new FhirPath(resource);

        it('should parse a simple path', function() {
            var parsed = fhirPath.parse('Bundle.entry.fullUrl');
            assert(parsed);
            assert(parsed.length === 1);
            assert(parsed[0].path);
            assert(parsed[0].path.length === 2);
            assert(parsed[0].path[0] === 'entry');
            assert(parsed[0].path[1] === 'fullUrl');
        });

var fs = require('fs')
var os = require('os')
var path = require('path')
var child = require('child_process')
var ansimd = require('ansimd')
var compare = require('../../compare.js')

var spawn = child.spawn
if (os.type() === 'Windows_NT') spawn = require('win-spawn')

var gasketCmd = path.resolve(__dirname, '..', '..', 'node_modules', 'gasket', 'bin.js')

exports.problem = ansimd(fs.readFileSync(path.join(__dirname, 'problem.md')).toString())
exports.solution = "Reference solution:\n\n" + fs.readFileSync(path.join(__dirname, 'package.json')).toString() + '\n'

exports.verify = function(args, cb) {
  var entry = spawnEntry(args)
  var solution = spawnSolution()
  compare(entry, solution, cb)
}

exports.run = function(args) {
  var entry = spawnEntry(args)
  console.error('gasket', 'run', '--config', path.resolve(args[0]))
  entry.stdout.pipe(process.stdout)
  entry.stderr.pipe(process.stderr)
}

function spawnEntry(args) {
  var entryCmd = gasketCmd

exports.loadConfig = () => {
  let configData = {};
  try {
    const configJSON = fs.readFileSync("config.json");
    configData = JSON.parse(configJSON);
  } catch (e) {
    niod_console.error(e);
    return;
  }
  for (const property of Object.keys(this.config)) {
    if (configData.property) {
      this.config[property] = configData[property];
    }
  }
  niod_console.log("Config file loaded");
};

const templatePath = './helper_scripts/templates/interfaces/component.d.mustache';
        const templateProps = { fileName, isClass, lowerFileName, isConnectStore };
        const pageDirPath = `${exports.Config.pageInterfaceDir}/${fileName}.d.ts`;
        const compDirPath = `${exports.Config.compInterfaceDir}/${fileName}.d.ts`;
        const pageInterfaceIndex = './helper_scripts/templates/interfaces/page-index.d.mustache';
        const compIntefaceIndex = './helper_scripts/templates/interfaces/component-index.d.mustache';
        const storeInterface = './helper_scripts/templates/interfaces/redux-store.d.mustache';
        const storeImportInterface = './helper_scripts/templates/interfaces/redux-import.d.mustache';
        const writeFileProps = {
            dirPath: isPage ? pageDirPath : compDirPath,
            getFileContent: () => exports.Helper.getTemplate(templatePath, templateProps),
            message: 'Added new interface file'
        };
        const replaceContentParams = {
            fileDir: `${exports.Config.interfaceDir}/index.ts`,
            filetoUpdate: fs.readFileSync(path.resolve('', `${exports.Config.interfaceDir}/index.ts`), 'utf8'),
            getFileContent: () => exports.Helper.getTemplate(isPage ? pageInterfaceIndex : compIntefaceIndex, templateProps),
            message: 'Interface file added to Interfaces/index.ts',
            regexKey: isPage ? /...PAGE INTERFACES/g : /...COMPONENT INTERFACES/g
        };
        const replaceStoreParams = {
            fileDir: `${exports.Config.reduxInterfaceDir}/Store.d.ts`,
            filetoUpdate: fs.readFileSync(path.resolve('', `${exports.Config.reduxInterfaceDir}/Store.d.ts`), 'utf8'),
            getFileContent: () => exports.Helper.getTemplate(storeInterface, templateProps),
            message: 'Interface file added to Interfaces/Redux/Store.d.ts',
            regexKey: /export type IStore\s[=]\s[{]/g
        };
        exports.Helper.writeFile(writeFileProps);
        exports.Helper.replaceContent(replaceContentParams);
        if (isConnectStore) {
            exports.Helper.replaceContent(replaceStoreParams);
            setTimeout(() => {

function oauthLazyHandshake (tokens, cb) {
  const file = this.opts.file || CREDENTIALS_FILENAME
  const fetchCredentials = setCredentials.call(this, cb)

  if (!tokens && fs.existsSync(file)) {
    tokens = JSON.parse(fs.readFileSync(file))
  }

  if (tokens && tokens.access_token) {
    return fetchCredentials(null, tokens)
  }

  getAccessToken.call(this, fetchCredentials)
}

function stylePlayer() {
  var theme = fs.readFileSync(path.join(__dirname, 'themes', 'theme.css'), "utf8");

  mainWindow.webContents.insertCSS('#player paper-icon-button[data-id="show-miniplayer"] { display: none; }');
  mainWindow.webContents.insertCSS(theme);
}

const fs = require('fs');
const present = require('present');

const targets = {
  vanilla: { module: require('./vanilla'), source: fs.readFileSync('./vanilla/index.js').toString() },
  vanillaPromote: { module: require('./vanilla-promote'), source: fs.readFileSync('./vanilla-promote/index.js').toString() },
  ts: { module: require('./ts'), source: fs.readFileSync('./ts/index.js').toString() },
  babel: { module: require('./es6/index-babel.js'), source: fs.readFileSync('./es6/index-babel.js').toString() },
  buble: { module: require('./es6/index-buble.js'), source: fs.readFileSync('./es6/index-buble.js').toString() },
  es6: { module: require('./es6/index.js'), source: fs.readFileSync('./es6/index.js').toString() },
};

const numLoops = 10;

let suites = [];
let executionTable = [];
let executionRow = [];

let memoryTable = [];
let memoryRow = [];
let previousMemory = null;
function addExecutionRow(elapsedTime) {
  executionRow.push(elapsedTime.toFixed(2) + "ms");

  let currentMemory = process.memoryUsage();