cached-bind.js

// calling this version of bind inside .render() should only create each bound function once
// WARNING: I didn't even ran this code :P so I'm not sure if it works 



const _cache = new WeakMap();
const _cmpArray = (arr1, arr2) => (arr1.length === arr2.length) && 
                                  (arr1.every((v,i)=> (v === arr2[i])));

function bind(fn, context, ...args) {
  
    if (!_cache.has(context))
      _cache.set(context, new Map());
    
    let componentCache = _cache.get(context);
  
    if (!componentCache.has(fn))
      componentCache.set(fn, [[args, fn.bind(context, ...args)]]); 
    
    let fragments = componentCache.get(fn);
    let fragment = fragments.find(([boundArgs]) => _cmpArray(boundArgs, args))
    
    if (fragment) 
      return fragment[1];
        
    fragment = [args, fn.bind(context, ...args)];
    fragments.push(fragment)
  
    return fragment[1];
}