recompose memoize function

memoizeFuncs.js

import mapValues from 'lodash/object/mapValues';
import every from 'lodash/collection/every';

const sortUsersByKey (users, key) => {
  //...
};

const upperCaseNames (users) => {
  // ...
};

OptimizedSortedUserList = useMemoizedLib({
  sortUsersByKey: sortUsersByKey,
  upperCaseNames: upperCaseNames
}, ({lib, users, key}) => {
  const transformedUsers = lib.upperCaseNames(users);
  const sortedUsers = lib.sortUsersByKey(transformedUsers, key);
  
  return <UserList users={sortedUsers} />
});




// Impl: 

const areArraysShallowEqual = (arr1, arr2) => {
  if (args.length !== lastArgs.length) {
    return false;
  }

  return every(arr1, (val, index) => val === arr2[index]);
};

const memoizeLast = (fn) => {
  let lastArgs = [];
  let lastResult = null;

  return (...args) => {
    if (areArraysShallowEqual(args, lastArgs)) {
      return lastResult;
    }

    lastArgs = args;
    lastResult = fn.apply(undefined, args);

    return lastResult;
  };
};

const memoizeFunctions = (functionsToMemoize, BaseComponent) => {
  return class extends React.Component {
    constructor(props, context) {
      super(props, context);
      this._memoizedFunctions = mapValues(functionsToMemoize, (fn) => memoizeLast(fn));
    },

    render() {
      return <BaseComponent lib={this._memoizedFunctions} {...this.props} />;
    }
  }
};