Gulp is not copying any html files in the build cmmand - angularjs

Question

gulp build command is copying and minifying all the JS and CSS files from my app folder into dist/ folder, but it is not copying any html Files into the dist folder.
I am using ng-route from angular .
Here is the code from my routes.js file :
module1.config(function ($routeProvider) {
$routeProvider
// route for the home page
.when('/', {
templateUrl: '/app/pages/home.html',
controller: 'mainController',
resolve: {
resolvedJSON: function (UserService) {
return UserService.getModelTable1();
}
});
Can someone help me as to why Gulp is not picking the html files during build?
My Gulpfile.js is :
const gulp = require('gulp');
const HubRegistry = require('gulp-hub');
const browserSync = require('browser-sync');
const conf = require('./conf/gulp.conf');
// Load some files into the registry
const hub = new HubRegistry([conf.path.tasks('*.js')]);
// Tell gulp to use the tasks just loaded
gulp.registry(hub);
gulp.task('inject', gulp.series(gulp.parallel('styles', 'scripts'), 'inject'));
gulp.task('build', gulp.series('partials', gulp.parallel('inject', 'other'), 'build'));
gulp.task('test', gulp.series('scripts', 'karma:single-run'));
gulp.task('test:auto', gulp.series('watch', 'karma:auto-run'));
gulp.task('serve', gulp.series('inject', 'watch', 'browsersync'));
gulp.task('serve:dist', gulp.series('default', 'browsersync:dist'));
gulp.task('default', gulp.series('clean', 'build'));
gulp.task('watch', watch);
/*
// JS hint task
gulp.task('jshint', function() {
gulp.src('./src/scripts/*.js')
.pipe(jshint())
.pipe(jshint.reporter('default'));
});
*/
// minify new images
gulp.task('imagemin', function() {
var imgSrc = './src/images/**/*',
imgDst = './build/images';
gulp.src(imgSrc)
.pipe(changed(imgDst))
.pipe(imagemin())
.pipe(gulp.dest(imgDst));
});
function reloadBrowserSync(cb) {
browserSync.reload();
cb();
}
function watch(done) {
gulp.watch([
conf.path.src('index.html'),
'bower.json'
], gulp.parallel('inject'));
gulp.watch(conf.path.src('app/**/*.html'), reloadBrowserSync);
gulp.watch([
conf.path.src('**/*.css')
], gulp.series('styles'));
gulp.watch(conf.path.src('**/*.js'), gulp.series('inject'));
done();
}
My build.js file is as below:
const gulp = require('gulp');
const filter = require('gulp-filter');
const useref = require('gulp-useref');
const rev = require('gulp-rev');
const revReplace = require('gulp-rev-replace');
const uglify = require('gulp-uglify');
const cssnano = require('gulp-cssnano');
const htmlmin = require('gulp-htmlmin');
const sourcemaps = require('gulp-sourcemaps');
const uglifySaveLicense = require('uglify-save-license');
const inject = require('gulp-inject');
const ngAnnotate = require('gulp-ng-annotate');
var changed = require('gulp-changed');
var imagemin = require('gulp-imagemin');
const conf = require('../conf/gulp.conf');
gulp.task('build', build);
// minify new images
gulp.task('imagemin', function() {
var imgSrc = './src/images/**/*',
imgDst = './build/images';
gulp.src(imgSrc)
.pipe(changed(imgDst))
.pipe(imagemin())
.pipe(gulp.dest(imgDst));
});
function build() {
const partialsInjectFile = gulp.src(conf.path.tmp('templateCacheHtml.js'), {read: false});
const partialsInjectOptions = {
starttag: '<!-- inject:partials -->',
ignorePath: conf.paths.tmp,
addRootSlash: false
};
const htmlFilter = filter(conf.path.tmp('**/*.html'), {restore: true});
const jsFilter = filter(conf.path.tmp('**/*.js'), {restore: true});
const cssFilter = filter(conf.path.tmp('**/*.css'), {restore: true});
return gulp.src(conf.path.tmp('/index.html'))
.pipe(inject(partialsInjectFile, partialsInjectOptions))
.pipe(useref())
.pipe(jsFilter)
.pipe(sourcemaps.init())
.pipe(ngAnnotate())
.pipe(uglify({preserveComments: uglifySaveLicense})).on('error', conf.errorHandler('Uglify'))
.pipe(rev())
.pipe(sourcemaps.write('maps'))
.pipe(jsFilter.restore)
.pipe(cssFilter)
.pipe(sourcemaps.init())
.pipe(cssnano())
.pipe(rev())
.pipe(sourcemaps.write('maps'))
.pipe(cssFilter.restore)
.pipe(revReplace())
.pipe(htmlFilter)
.pipe(htmlmin())
.pipe(htmlFilter.restore)
.pipe(gulp.dest(conf.path.dist()));
}