Lodash optimization

[wmcmurray]

When you do import _ from 'lodash' the whole lodash lib gets included in the bundled files and it weights a lot. By importing only the functions used, I was able to go from this :

dist/vue-scroll.js 532.04kb
dist/vue-scroll.min.js 70.56kb (gzipped: 24.53kb)
dist/vue-scroll.common.js 4.23kb
dist/vue-scroll.esm.js 4.08kb

to this :

dist/vue-scroll.js 23.30kb
dist/vue-scroll.min.js 4.59kb (gzipped: 2.02kb)
dist/vue-scroll.common.js 4.54kb
dist/vue-scroll.esm.js 4.29kb

Which is a pretty good improvement if you ask me 🙂 !

[wangpin34]

Looks good to me. Thanks for your great work. 👍