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JavaScript Interacting with the DOM Traversing the DOM Getting All Children of a Node with children

Posted by Samuel Kleos
.a{fill-rule:evenodd;}techdegree
Samuel Kleos
Front End Web Development Techdegree Student 12,719 Points

Uncaught TypeError: li.appendChild is not a function

Why doesn't my for..in loop work here?

const taskList = document.querySelector('.list-container ul');
const listItems = taskList.children;

// Adding a remove button to a li item.
function addBtnRemove(li) {
    let btnRemove = document.createElement('button');
    btnRemove.className = 'remove';
    btnRemove.textContent = "Remove";
    li.appendChild(btnRemove);
}

// Adding a remove button to existing li items
for (let item in listItems ) {
    addBtnRemove(item);
}

1 Answer

Steven Parker
Steven Parker
229,644 Points
Steven Parker
Steven Parker
229,644 Points

The loop variable (item in this case) of a "for...in" loop will contain a stringified index for each item, but the addBtnRemove function apparently expects to get an element reference as an argument.

Did you perhaps mean to use "for...of" instead?

Samuel Kleos
.a{fill-rule:evenodd;}techdegree
Samuel Kleos
Front End Web Development Techdegree Student 12,719 Points

That's fantastic, I just implemented it thank you.