Error: ENOENT: no such file or directory, open 'target/tmp/templates.js'

[Soumya-mp]

I am running a gulp build for production. I am getting an error "Error: ENOENT: no such file or directory, open 'target/tmp/templates.js'". This is a snippet of gulpfile.js and gulp/build.js files
GULPFILE.JS

gulp.task('html', function () {
    return gulp.src(config.app + 'app/**/*.html')
        .pipe(print())
        .pipe(htmlmin({collapseWhitespace: true}))
        .pipe(templateCache('templates.js', {
            module: 'mommypowerApp',
            root: 'app/',
            moduleSystem: 'IIFE',
        }))
        .pipe(gulp.dest(config.tmp));
});

GULP/BUILD.JS

module.exports = function() {
    var templates = fs.readFileSync(config.tmp + '/templates.js');
    var manifest = gulp.src(config.revManifest);

    return gulp.src([config.app + '**/*.html',
        '!' + config.app + 'app/**/*.html',
        '!' + config.app + 'swagger-ui/**/*',
        '!' + config.bower + '**/*.html'])
        .pipe(print())
        .pipe(plumber({errorHandler: handleErrors}))
        //init sourcemaps and prepend semicolon
        .pipe(useref({}, initTask))
        //append html templates
        .pipe(gulpIf('**/app.js', footer(templates)))
        .pipe(gulpIf('*.js', jsTask()))
        .pipe(gulpIf('*.css', cssTask()))
        .pipe(gulpIf('*.html', htmlmin({collapseWhitespace: true})))
        .pipe(gulpIf('**/*.!(html)', rev()))
        .pipe(revReplace({manifest: manifest}))
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest(config.dist));
};

Not able to understand why fs.readFileSync is failing.