Deserialize String JS Fundamentals

function deserializeString(arr) {
    let result = "";
    let data = {};
    for (let i = 0; i < arr.length; i++) {
        let input = arr[i];
        if (input === "end") {
            break;
        }
        let parts = input.split(":");
        let letter = parts[0];
        let indices = parts[1].split("/");
        for (let j = 0; j < indices.length; j++) {
            let index = indices[j];
            data[index] = letter;
        }
    }
    let sortedIndices = Object.keys(data).sort((a, b) => a - b);
    for (let i = 0; i < sortedIndices.length; i++) {
        let index = sortedIndices[i];
        result += data[index];
    }
    console.log(result);
}