JSFiddle - React, Tailwind, and code Playground

JavaScript

var myFunction = function (param) {
    myFunction.cache = myFunction.cache || {};
    if (!myFunction.cache[param]) {
        var result = {result: 'calculation for '+param};
        // .. expensive calculation ..
        myFunction.cache[param] = result
    }
    return myFunction.cache[param];
}

console.log(myFunction("test"));
console.log(myFunction("test")); // do the same function call
console.log(myFunction("test 123")); // another call

console.log(JSON.stringify(myFunction.cache)); 
// {"test":{"result":"calculation for test"},"test 123":{"result":"calculation for test 123"}}