JavaScript递归无法跳出：JSON递归搜索更新问题求助

Let's work through this together—your code is close, but there are a few key issues stopping it from working as expected:

What's Going Wrong? #

1. Recursive results aren't updating the parent status
   When you call findAndUpdate(id, array.children, title) inside the map callback, you're returning its result, but you never assign that result to the outer status variable. So even if the recursive call finds the matching ID, the parent function's status stays false.

2. You're not actually updating the title
   Your function's goal is to update the title for the matching ID, but that critical step is missing from your code.

3. map isn't the right tool for this job
   map is designed to transform arrays into new arrays, not for side effects (like updating data) or early termination. You're looping through every item even after finding a match, which is inefficient.

Fixed Code #

Here's the corrected version with explanations for each change:

var data = {
    treeData: [
        {
            title: 'United States of America',
            children: [{
                title: 'Chicago', id:4, editOn:false, children:[{ title: 'New Mexico', id:17, editOn:false }]
            },{ title: 'New York', id:3, editOn:true }],
            id:0, editOn:false
        },
        {
            title: 'United Arab Emirate',
            children: [{ title: 'Abu Dhabi', id:5, editOn:true }],
            id:1, editOn:true
        },
        {
            title: 'United Kingdom',
            children: [{ title: 'London', id:7, editOn:false },{ title: 'Hampshire', id:6, editOn:true }],
            id:2, editOn:false
        },
    ]
};

function findAndUpdate(id, data, newTitle) {
    let status = false;
    // Use for...of instead of map to allow early termination
    for (const item of data) {
        console.log(item.id, id, "children" in item, status);
        if (item.id === id) {
            console.log("Match Found");
            // Update the title for the matching item
            item.title = newTitle;
            status = true;
            // Stop checking further items once we find a match
            break;
        }
        // Only recurse if the item has non-empty children
        if ("children" in item && item.children.length > 0) {
            // Assign the recursive result to status
            status = findAndUpdate(id, item.children, newTitle);
            // If the recursive call found a match, exit the parent loop
            if (status) break;
        }
    }
    return status;
}

var s = findAndUpdate(5, data.treeData, "India");
console.log(s); // Logs true
console.log(data.treeData[1].children[0].title); // Logs "India"

Key Changes Explained #

• Switched to for...of: This lets us break out of the loop as soon as we find our match, avoiding unnecessary iterations.
• Added title update: The line item.title = newTitle fulfills your core requirement of updating the title for the matching ID.
• Propagated recursive status: When we call the function on an item's children, we assign the return value to status. If the recursive call finds a match, we immediately break out of the parent loop to stop searching.
• Added non-empty children check: A small safeguard to avoid calling the function on empty children arrays (prevents unnecessary recursive calls).

Why Your Original Code Returned false #

Even when the recursive call found the matching ID, the outer status variable never got updated. The map callback returns the result, but map just collects those returns into a new array (which you weren't using). The outer status remained false because it was never modified by the recursive call.

内容的提问来源于stack exchange，提问作者MD Danish