contain-element/gulpfile.js

const gulp = require("gulp"),
    ugly = require("gulp-uglify"),
    concat = require("gulp-concat"),
    insert = require("gulp-insert");

gulp.task("module", function() {
    return gulp.src([ "contain-element.js" ])
        .pipe(insert.transform(function(contents) {
            return contents
                .replace(/^function ContainElement/, "module.exports = function")
                .replace(/\n\}/, "\n};");
        }))
        .pipe(concat("contain-element-module.js"))
        .pipe(gulp.dest("./"));
});

gulp.task("minify", function() {
    return gulp.src("contain-element.js")
        .pipe(ugly())
        .pipe(concat("contain-element.min.js"))
        .pipe(gulp.dest("./"));
});

gulp.task("default", gulp.parallel(
    "module",
    "minify"
));