I did a 'lein uberjar' on a small new Luminus project (with +cljs) and app.js is 1.5MB! Is this expected? Looking at the file's contents, it seems that a lot of it is react's exports, starting with:

!function(e,t){"object"==typeof exports&&"object"==typeof module?module.exports=t(require("React"),require("ReactDOM")):"function"==typeof define&&define.amd?define(["React","ReactDOM"],t):"object"==typeof exports?exports.semanticUIReact=t(require("React"),require("ReactDOM")):e.semanticUIReact=t(e.React,e.ReactDOM)}(this,function(e,t){return function(e){function t(r){if(n[r])return n[r].exports;var a=n[r]={i:r,l:!1,exports:{}};return e[r].call(a.exports,a,a.exports,t),a.l=!0,a.exports}var n={};return t.m=e,t.c=n,t.d=function(e,n,r){t.o(e,n)||Object.defineProperty(e,n,{configurable:!1,enumerable:!0,get:r})},t.n=function(e){var n=e&&e.__esModule?function(){return e.default}:function(){return e};return t.d(n,"a",n),n},t.o=function(e,t){return Object.prototype.hasOwnProperty.call(e,t)},t.p="/",t(t.s=371)}([/*!*****************************************!*\
  !*** ./node_modules/process/browser.js ***!
  \*****************************************/
/*! dynamic exports provided */
/*! all exports used */
function(e,t){function n(){throw new Error("setTimeout has not been defined")}function r(){throw new Error("clearTimeout has not been defined")}function a(e){if(c===setTimeout)return setTimeout(e,0);if((c===n||!c)&&setTimeout)return c=setTimeout,setTimeout(e,0);try{return c(e,0)}catch(t){try{return c.call(null,e,0)}catch(t){return c.call(this,e,0)}}}function o(e){if(d===clearTimeout)return clearTimeout(e);if((d===r||!d)&&clearTimeout)return d=clearTimeout,clearTimeout(e);try{return d(e)}catch(t){try{return d.call(null,e)}catch(t){return d.call(this,e)}}}function l(){m&&p&&(m=!1,p.length?h=p.concat(h):y=-1,h.length&&u())}function u(){if(!m){var e=a(l);m=!0;for(var t=h.length;t;){for(p=h,h=[];++y<t;)p&&p[y].run();y=-1,t=h.length}p=null,m=!1,o(e)}}function i(e,t){this.fun=e,this.array=t}function s(){}var c,d,f=e.exports={};!function(){try{c="function"==typeof setTimeout?setTimeout:n}catch(e){c=n}try{d="function"==typeof clearTimeout?clearTimeout:r}catch(e){d=r}}();var p,h=[],m=!1,y=-1;f.nextTick=function(e){var t=new Array(arguments.length-1);if(arguments.length>1)for(var n=1;n<arguments.length;n++)t[n-1]=arguments[n];h.push(new i(e,t)),1!==h.length||m||a(u)},i.prototype.run=function(){this.fun.apply(null,this.array)},f.title="browser",f.browser=!0,f.env={},f.argv=[],f.version="",f.versions={},f.on=s,f.addListener=s,f.once=s,f.off=s,f.removeListener=s,f.removeAllListeners=s,f.emit=s,f.prependListener=s,f.prependOnceListener=s,f.listeners=function(e){return[]},f.binding=function(e){throw new Error("process.binding is not supported")},f.cwd=function(){return"/"},f.chdir=function(e){throw new Error("process.chdir is not supported")},f.umask=function(){return 0}},/*!************************!*\
  !*** external "React" ***!
  \************************/