Функция подобия

mapNumberToRange.js

function mapNumberToRange(number, target, condition) {
    const targetMin = Math.min(...target);
    const targetMax = Math.max(...target);
    const conditionMin = Math.min(...condition);
    const conditionMax = Math.max(...condition);
    if (number > conditionMax) number = conditionMax
    if (number < conditionMin) number = conditionMin
    const targetSize = target[1] - target[0];
    const conditionSize = condition[1] - condition[0];
    let mappedNumber = 0;
    if (targetSize > 0 && conditionSize > 0) {
        mappedNumber = Math.floor((number - condition[0]) * (targetSize / conditionSize) + target[0]);
    } else if (targetSize < 0 && conditionSize > 0) {
        mappedNumber = Math.floor((number - condition[0]) * (targetSize / Math.abs(conditionSize)) + target[0]);
    } else if (targetSize > 0 && conditionSize < 0) {
        mappedNumber = Math.floor((number - condition[0]) * (Math.abs(targetSize) / conditionSize) + target[0]);
    } else if (targetSize < 0 && conditionSize < 0) {
        mappedNumber = Math.floor((number - condition[0]) * (Math.abs(targetSize) / Math.abs(conditionSize)) + target[0]);
    }
    if (mappedNumber > targetMax) mappedNumber = targetMax
    if (mappedNumber < targetMin) mappedNumber = targetMin
    return Math.round(mappedNumber);
}

console.log(mapNumberToRange(0, [16, 5],[0, 1000])); // Вывод: 16
console.log(mapNumberToRange(1000, [16, 5],[0, 1000])); // Вывод: 5
console.log(mapNumberToRange(500, [16, 5],[0, 1000])); // Вывод: 10