How to get the index of the function in an array of functions which executed the fastest in JavaScript ?
Last Updated :
30 Dec, 2022
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In this example, we will learn how to get the index of the function in an array of functions that is executed the fastest in JavaScript.
Example:
Input: fun[] = [ hello, hello1, hello2 ] Output: index of fastest is 0. Explanation: Function hello execute fastest in all functions. Input: fun[] = [ while1, while2, while3 ] Output: index of fastest function is 2
Approach: The below steps have to be followed to solve the problem:
- We will first Iterate over the given array.
- We will find the time taken by each function and store it in a different array with the same index value as the function index. The time taken can be found by getting the difference in time using the performance.now() method.
- Finally, we print the minimum index by getting the minimum value of the array using the Math.min() method.
Example 1: In this example, we will calculate the time taken by each function to execute. We will then print the index of the fastest function. using the above-mentioned approach
<script>
// 1st function
function hello() {
var s = "";
var ans = ["The", " hello function ", "takes "];
for (var i = 0; i < 3; i++) s += ans[i];
console.log(s);
}
// 2nd function
function hello1() {
var s = "";
var ans = ["The hello1 function", " takes "];
for (var i = 0; i < 2; i++) s += ans[i];
console.log(s);
}
// 3rd function
function hello2() {
var ans = "The hello2 function takes ";
for (var i = 0; i < 1; i++) console.log(ans);
}
// Function to check time required by each function
function findTime(f) {
// Storing initial time in start
var start = performance.now();
// Calling the function
f();
// Storing time after running the function
var end = performance.now();
// Return time taken by function
return end - start;
}
function findMinTime() {
// Initializing array of functions
var fun = [hello, hello1, hello2];
// Initialising array of time taken by function
var ans = [];
// Iterating over all the functions and
// storing time taken by them
for (var i = 0; i < 3; i++) {
var n = findTime(fun[i]);
ans[i] = n;
console.log(ans[i]);
}
// Finding the minimum time in array
var answer = Math.min.apply(null, ans);
c = ans.indexOf(answer);
// Return index of fastest array
return c;
}
var minTime = findMinTime();
console.log("Index of fastest function:", minTime);
</script>
Output:
"The hello function takes " 0.10000000009313226 "The hello1 function takes " 0 "The hello2 function takes " 0 "Index of fastest function:" 1
Example 2: In this example, we will calculate the time taken by functions to perform some mathematical operations. We will then print the index of the fastest function.
<script>
// 1st function
function fac(n) {
let fact = 1;
for (let i = 1; i <= 4; i++)
fact *= i;
console.log("Factorial of 4 is:", fact);
}
// 2nd function
function fibo() {
let fab = 0;
let j = 1;
for (let i = 2; i <= 6; i++) {
let temp = fab;
fab += j;
j = temp;
}
console.log("6th fibonacci no is:", fab);
}
// 3rd function
function binpow() {
let j = 2;
let k = 22;
for (let i = 0; i < k; i++)
j = ((j * j) % 1e9) + 7;
console.log(
"Power 2 to 22 mod 1e9+7 is:", j
);
}
// Function to check time required
// by each function
function findTime(f) {
// Storing initial time in start
var start = performance.now();
// Calling the function
f();
// Storing time after running the function
var end = performance.now();
// Return time taken by function
return end - start;
}
function findMinTime() {
// Initializing array of functions
var fun = [fac, fibo, binpow];
// Initialising array of time
// taken by function
var ans = [];
// Iterating over all the functions
// and storing time taken by them
for (var i = 0; i < 3; i++) {
var n = findTime(fun[i]);
ans[i] = n;
console.log(ans[i]);
}
// Finding the minimum time in array
var answer = Math.min.apply(null, ans);
c = ans.indexOf(answer);
// Return index of fastest array
return c;
}
var minTime = findMinTime();
console.log("Index of fastest function:",
minTime);
</script>
Output:
Factorial of 4 is: 24 0.30000001192092896 6th fibonacci no is: 5 0.20000001788139343 Power 2 to 22 mod 1e9+7 is: 221047735 0.30000001192092896 Index of fastest function: 1
