Why such the large size of the js file after you gulp?

Good afternoon. Collect one js file from the 3: 2 libraries (jQuery and Materializ) and my file where I specify in which order to load them. Original weight jquery - 260kb, materializ - 300kb, my file 132b. Why do I get the file weighing in at 1.5 MB?
Here is my gulp:
var gulp = require('gulp'),
 cssmin = require('gulp-minify-css'),
 prefixer = require('gulp-autoprefixer'),
 uglify = require('gulp-uglify'),
 sass = require('gulp-sass'),
 watch = require('gulp-watch'),
 sourcemaps = require('gulp-sourcemaps'),
 rigger = require('gulp-rigger');

var path = {
 build: {
 html: 'build/',
 js: 'build/js/',
 css: 'build/css/',
},
 src: {
 html: 'src/*.html',
 js: 'src/js/main.js',
 style: 'src/style/main.scss',
},
 watch: {
 html: 'src/**/*.html',
 js: 'src/js/**/*.js',
 style: 'src/style/**/*.scss',
}
};

gulp.task('html:build', function () {
gulp.src(path.src.html)
.pipe(rigger())
.pipe(gulp.dest(path.build.html));
});

gulp.task('js:build', function () {
gulp.src(path.src.js)
.pipe(rigger())
.pipe(sourcemaps.init())
.pipe(uglify())
.pipe(sourcemaps.write())
.pipe(gulp.dest(path.build.js));
});

gulp.task('style build', function () {
gulp.src(path.src.style)
.pipe(sourcemaps.init())
.pipe(sass())
.pipe(prefixer())
.pipe(cssmin())
.pipe(sourcemaps.write())
.pipe(gulp.dest(path.build.css));
});


gulp.task('build', [
'html:build',
'js:build',
'style:build'
]);

gulp.task('watch', function () {
 watch([path.watch.html], function (event, cb) {
gulp.start('html:build');
});
 watch([path.watch.style], function (event, cb) {
gulp.start('style:build');
});
 watch([path.watch.js], function (event, cb) {
gulp.start('js:build');
});
});

gulp.task('default', ['build', 'watch']);
July 2nd 19 at 17:04
1 answer
July 2nd 19 at 17:06
Solution
Because sourcemaps

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