Reverse the word in a sentence

let s = "HELLO WORLD";
let end = s.length - 1;
let result = "";

for (let i = end; i >= 0; i--) {

    if (s[i] === ' ' || i === 0) {

        let start;

        if (i === 0) start = 0;
        else start = i + 1;

        // add space only if needed
        if (result !== "") {
            result += " ";
        }

        for (let j = start; j <= end; j++) {
            result += s[j];
        }

        end = i - 1;
    }
}

console.log(result);

let sen = "Who Is Priya";
let start = 0;
let end = sen.length - 1;
let result = "";

for (let i = end; i >= 0; i--) {

    if (sen[i] === ' ' || i === 0) {

        if (i === 0) {
            start = 0;
        } else {
            start = i + 1;
        }

        // add space only if result is not empty
        if (result !== "") {
            result += " ";
        }

        for (let j = start; j <= end; j++) {
            result += sen[j];
        }

        end = i - 1;
    }
}

console.log(result);

let s = "HELLO WORLD";
let end = s.length - 1;
let result = "";

for (let i = end; i >= 0; i--) {

    if (s[i] === ' ' || i === 0) {

        let start;

        if (i === 0) start = 0;
        else start = i + 1;

        // add space only if needed
        if (result !== "") {
            result += " ";
        }

        // change is here: reverse characters
        for (let j = end; j >= start; j--) {
            result += s[j];
        }

        end = i - 1;
    }
}

console.log(result);