Why are the functions wrongly comparing the masses?

[Cleofas]

I have the following function to compare the masses:

a = [1,'a']
b = [1,'b']
function compareArrays(arr1, arr2) {

let c = 0;

if (arr1.length == arr2.length) {

for(let i = 0; i <= arr1.length; i++) {

if (arr1[i] === arr2[i]) {

c++;

console.log(c)

}

}
    if (c === arr1.length) {
            return true;
    }
} return false;

}
console.log(compareArrays(a, b))

I expect to get false, because the second elements of the masses don't match, but they get true. Why and how to fix it?

[authera]

Subject problem i <= arr1.length♪ As a result, the cycle is carried out 3 times, not 2. And we get the dope. if (undefined === undefined ) { c++

To find such mistakes, learn. https://ru.stackoverflow.com/a/701140/191482