asassds

function solve(input) {
    let text = input.shift();

    const isValidIndex = (index) => {
        return index >= 0 && index < text.length;
    };

    const replace = (currentChar, newChar) => {
        while (text.search(currentChar) !== -1) {
            text = text.replace(currentChar, newChar)
        }

        return text;
    }

    const cut = (startIndex, endIndex) => {
        startIndex = Number(startIndex);
        endIndex = Number(endIndex);

        if (isValidIndex(startIndex) && isValidIndex(endIndex)) {
            text = text.substring(0, startIndex) + text.substring(endIndex + 1);

            return text;
        } else {
            return 'Invalid indexes!';
        }
    }

    const make = (type) => {
        type === 'Upper'
            ? text = text.toUpperCase()
            : text = text.toLowerCase();

        return text;
    }

    const check = (string) => {
        return text.search(string) !== -1
                ? `Message contains ${string}`
                : `Message doesn't contain ${string}`;
    }

    const sum = (startIndex, endIndex) => {
        startIndex = Number(startIndex);
        endIndex = Number(endIndex);

        if (isValidIndex(startIndex) && isValidIndex(endIndex)) {
            return [...text.substring(startIndex, endIndex + 1)]
                    .reduce((acc, current) => {
                        return acc + current.charCodeAt(0);
                    }, 0)
        } else {
            return 'Invalid indexes!';
        }
    }

    const cmdParser = {
        replace,
        make,
        cut,
        check,
        sum
    };

    input
        .forEach(line => {
            if (line !== 'Finish') {
                const tokens = line.split(' ');
                const cmd = tokens.shift().toLowerCase();

                console.log(
                    cmdParser[cmd](...tokens)
                );
            }
        });
}