Lodash Memoize Only First Parameter Prototype

memoize-prototype.js

var _ = require("lodash")

var myMerge = (leftObject, rightObject) => {
   return {
        left: leftObject.left,
        right: rightObject.right,
   }
};

var memoizedMyMerge = _.memoize(myMerge);

var leftObject = {
left: 1,
right: 2,
};

var rightObject = {
left: 3,
right: 4,
};

var result = memoizedMyMerge(leftObject, rightObject);
result;

var newRightObject = Object.assign({}, rightObject, {
right: 5,
});
var rightMemoizedResult = memoizedMyMerge(leftObject, newRightObject);
rightMemoizedResult;

var newLeftObject = Object.assign({}, leftObject, {
left: 5,
});
var leftMemoizedResult = memoizedMyMerge(newLeftObject, rightObject);
leftMemoizedResult;

I ran this code in RunKit https://npm.runkit.com/lodash.memoize