Function optimization techniques that produce fixed results in Javascript_javascript techniques

Share an optimization technique for writing functions in Javascript.
Applicable functions should meet the following conditions:
Produce fixed results
Multiple calls on the page
Complex or time-consuming
The code and analysis are as follows :
Java code:

Copy code The code is as follows:

// Functions that produce fixed results and are called multiple times on the page
function check() {
//Simulate time-consuming operations
var begin = Date.now(); //Added by ECMAScript5, if not supported Please change to new Date();
var ONE_SECOND = 1000,
result = false;
while(true) {
if(Date.now() - begin >= ONE_SECOND){
result = true;
break;
}
}
//Function rewrite, return the result directly
check = function() {
return result;
}
return result;
}
var firstBegin = Date.now();
check(); //First function call
var firstEnd = Date.now();
check(); //The second function call
var secondEnd = Date.now();
console.log("The first function takes time:" (firstEnd - firstBegin) "ms.");
console.log("The second function takes time:" (secondEnd - firstEnd) "ms.");

The results are displayed as follows: