title: How to import just the functions i need and tree shake
body: <p>I am trying to import 2 functions from date-fns (using webpack 4 and babel). 
  When I analyze my <strong>prod</strong> build the whole library is added to the bundle.</p>
  
  <p>First I have tried importing with <code>import { format, max } from 'date-fns';</code> and  setting "module" to false in Babel's presets <code>@babel/preset-env</code>, since Webpack doc says this could hinder treeshaking.</p>
  
  <p>Also tried importing by <code>import max from 'date-fns/max';</code></p>
  
  <p>I expected Webpack to be able to remove all functions but the imported ones, since modularity is one of <code>date-fns</code> selling points. 
  Can´t think of what I am doing wrong at the moment. </p>
  
  <p>Could someone please share their experience or solutions for this?</p>
  
  <p>Adding 170kb for using two functions is not acceptable.</p>