这是我的递归函数中的问题吗？

Question

I need to run through a stack of HTML Elements. But all my attempts to write a recursive function didn't work.

In the snippet below I cannot return value from if statement and afterwards from a function itself.

I can console.log the information I need, it gets there, but trying to return it, it doesn't work.

I never had such an issue with returning some data that's why I decided to display it here so as to let a fresh-eye to revise the code.

function findElementByDataValue(target: EventTarget, data: {key: string, value: string}){

    if (target.dataset[data.key] === data.value) {
      return target;
    };

    if (target.children.length > 0) {

      for (const child in target.children) {
        const element = target.children[child];

        // I tried to return "recursive" function here too. "Return" Abrupt execution (as it should)
        if (element.children && typeof element === 'object') {
          findElementByDataValue(element, data);
        }

      }

    }

}

if you have any ideas or noticed an issue with my recursive function, I would appreciate any help.

Answer 1

Using the return keyword like you are doing.

Your second function calls the first function without returning the value returned by the first function:

Replace

    if (element.children && typeof element === 'object') {
      findElementByDataValue(element, data);
    }

with:

    if (element.children && typeof element === 'object') {
      return findElementByDataValue(element, data);
    }

In general, run your code in a debugger (popular web browsers provide debuggers) to see what is going on.

See some debuggers documentation:

• https://developer.mozilla.org/en-US/docs/Tools/Debugger
• https://developers.google.com/web/tools/chrome-devtools/javascript/

If you are new to JavaScript, I suggest looking into unit testing and test-driven development .

Writing tests (early) will help you think of what can go wrong with your code and write more robust functions. Jasmine is nice, this article suggests many other JavaScript unit testing options