CODEWITHSUNDEEP
javascriptajax
Car981
Car981

Reputation: 261

Possible infinite recursion in method?

In the following code, why is it that it could create a possible infinite recursion, and why does the memory usage keep raising, and how to solve it ?

function waitForKeyElements (selectorTxt, actionFunction) {
    if (getElementByXPath(selectorTxt) == null) {
       var timeControl = setInterval (function () {
                    waitForKeyElements (selectorTxt, actionFunction);
                },
                300
            );
    } else {
        clearInterval (timeControl);
        actionFunction();
    }
}

Upvotes: 0

Views: 113

Answers (1)

techfoobar
techfoobar

Reputation: 66673

The variable timeControl is local to each invocation of the function waitForKeyElements() - i.e. the timeControl you set will not be the timeControl you clear. In other words, the timer you started with setInterval will never get cleared.

Moving it outside the function should solve it.

i.e.

var timeControl = -1;

function waitForKeyElements (selectorTxt, actionFunction) {
    if (getElementByXPath(selectorTxt) == null) {
       timeControl = setInterval (function () {
                    waitForKeyElements (selectorTxt, actionFunction);
                },
                300
            );
    } else {
        if(timeControl !== -1) clearInterval (timeControl);
        actionFunction();
    }
}

Also, as user Prinzhorn pointed out in the comment, starting a timer with setInterval in each invocation is bound to be troublesome. You should really be just doing a setTimeout to ensure things don't get out of hand.

Upvotes: 2

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