JavaScript global dynamic variable undefined from function to function, seems to be local scope

Question

I'm having an issue with the interaction of these two functions. They are used in onclick calls of elements. Essentially (because of things outside my control) I need to remember when and what has hidden an element.

Everything is working exactly as I want, except for the undefined check in the show function. I create a global variable when I hide things and I want to use that again when I'm looking to show things. The only issue I have is that in the show function, it seems what I thought was a global variable is not.

function branchShow(targetID, triggerID){
    var target = document.getElementById(targetID);
    var trigger = document.getElementById(triggerID);
    var parentID = trigger.parentElement.parentElement.parentElement.parentElement.id;
    var globalMemory = "wasIHiddenBefore_" + parentID

    if (typeof window[globalMemory] !== "undefined"){
        if (window[globalMemory]) {
            console.log(globalMemory + " is evaluated true");
            window[globalMemory] = false;
        } else {
            console.log(globalMemory + " is evaluated false");
            target.setAttribute("style","display: block;");
        }
    } else {
        console.log(globalMemory + " is undefined");
        target.setAttribute("style","display: block;");
    }
};

function branchHide(targetID, triggerID){
    if (typeof i !== "undefined" ) {var iMemory = i;}
    if (typeof j !== "undefined" ) {var jMemory = j;}
    if (typeof k !== "undefined" ) {var kMemory = k;}
    var target = document.getElementById(targetID);
    target.setAttribute("style","display: none;");

    //don't want to flag on load
    if (hasLoadFinished){
        window["wasIHiddenBefore_" + targetID] == true;
        console.log("wasIHiddenBefore_" + targetID + " created as true");
    }
    .
    .
    .

The console output from a sample execution is below. The 4th and the 6th line are the most critical in displaying the issue.

wasIHiddenBefore_1e16f2513f7842d5be352ca01b5c1c3f is undefined
wasIHiddenBefore_f82bdc0c527541e68fc405e9ac70015b is undefined
wasIHiddenBefore_2d869e44f4c44454a8415eecbd64061e created as true
wasIHiddenBefore_f82bdc0c527541e68fc405e9ac70015b created as true
wasIHiddenBefore_1e16f2513f7842d5be352ca01b5c1c3f is undefined
wasIHiddenBefore_f82bdc0c527541e68fc405e9ac70015b is undefined

Does anyone know why I'm seeing what I'm seeing and what I can do to make these dynamic variables act globally from function to function? Thanks.

Answer 1

window["wasIHiddenBefore_" + targetID] == true; is a comparison, not an assignment. Despite logging "… created as true" you never set the variable. You want window["wasIHiddenBefore_" + targetID] = true;.