One problem on build dsteem

[sityck]

I am trying to build the dsteem.
but when use 'npm run prepublishOnly' ,It report an error:

$ npm run prepublishOnly

> @steemit/[email protected] prepublishOnly /home/sdu/web/dsteem
> make all

tsc -p tsconfig.json --outDir lib && \
VERSION="$(node -p 'require("./package.json").version')"; \
echo "module.exports = '${VERSION}';" > lib/version.js
touch lib
browserify src/index-browser.ts --debug --full-paths \
	--standalone dsteem --plugin tsify \
	--transform [ babelify --extensions .ts ] \
	| derequire > dist/dsteem.js
uglifyjs dist/dsteem.js \
	--source-map "content=inline,url=dsteem.js.map,filename=dist/dsteem.js.map" \
	--compress "dead_code,collapse_vars,reduce_vars,keep_infinity,drop_console,passes=2" \
	--output dist/dsteem.js || rm dist/dsteem.js

Parse error at dist/dsteem.js:3078,0
const Buffer = _dereq_('safe-buffer').Buffer
^
ERROR: Unexpected token: keyword (const)
    at JS_Parse_Error.get (eval at <anonymous> (/home/sdu/web/dsteem/node_modules/uglify-js/tools/node.js:21:1), <anonymous>:73:23)
    at fatal (/home/sdu/web/dsteem/node_modules/uglify-js/bin/uglifyjs:291:53)
    at run (/home/sdu/web/dsteem/node_modules/uglify-js/bin/uglifyjs:235:9)
    at Object.<anonymous> (/home/sdu/web/dsteem/node_modules/uglify-js/bin/uglifyjs:160:5)
    at Module._compile (module.js:624:30)
    at Object.Module._extensions..js (module.js:635:10)
    at Module.load (module.js:545:32)
    at tryModuleLoad (module.js:508:12)
    at Function.Module._load (module.js:500:3)
    at Function.Module.runMain (module.js:665:10)
gzip -9 -f -c dist/dsteem.js > dist/dsteem.js.gz
gzip: dist/dsteem.js: No such file or directory
Makefile:32: recipe for target 'dist/dsteem.js.gz' failed
make: *** [dist/dsteem.js.gz] Error 1
npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! @steemit/[email protected] prepublishOnly: `make all`
npm ERR! Exit status 2

Does anyone know how to fix it?
I hava not changed the code of dsteem,
OR , Is there another way to build dsteem with dsteem.js?