Hard To Test Code

hard-to-test-code.js

// BAD
function valIncrementer(val, disabled) {
    var nextVal = val + 1

    function firstStageSetter1() {
        if(val >= 10) {
            nextVal = 10 //clip it to high limit value
            secondStageSetter()
        }
    }
    function firstStageSetter2() {
        if(val <= 0) {
            nextVal = 0 //clip it to low limit value
            secondStageSetter()
        }
    }
    function secondStageSetter() {
        if(disabled) {
            nextVal = val
        }
    }
    function run() {
        firstStageSetter1()
        firstStageSetter2()
    }
    
    run()
    return nextVal
}