如何统计对象中typeof值为'object'的属性数量？附遍历代码

Hey there! I see you're working with a deeply nested object/array structure and need to count how many properties have a typeof value of 'object'. Let's fix your current code and also show a more scalable recursive approach—hardcoding nested $.each calls can get messy if your structure has variable depth!

First: Fixing Your Existing Code #

Your traversal logic is already laying the groundwork, you just need to add a counter and handle a critical edge case (JavaScript quirk: typeof null returns 'object', which you probably don't want to count). Here's the adjusted version:

// Initialize a counter outside the loops to track the total
let objectCount = 0;

$.each(Obj, function(k,v){ 
  $.each(v, function(j,l){ 
    $.each(l, function(r,s){ 
      // Check for object type, exclude null, and optionally exclude arrays
      if(l.hasOwnProperty(r) && typeof s === 'object' && s !== null) {
        // Add && !Array.isArray(s) here if you don't want to count arrays
        objectCount++;
      } 
    }) 
  }) 
});

console.log(`Total object-type properties: ${objectCount}`);

Better: Use a Recursive Function (For Any Depth) #

Hardcoding three layers of $.each only works if your structure is exactly three levels deep. A recursive function will automatically handle any nested depth, making your code way more flexible and maintainable.

Here's a reusable solution:

function countObjectProperties(targetObj) {
  let totalCount = 0;

  // Recursive helper to traverse every nested item
  function traverse(item) {
    // Skip null (since typeof null incorrectly returns 'object')
    if (item === null) return;

    // Only process objects/arrays
    if (typeof item === 'object') {
      $.each(item, (key, value) => {
        // Check if the current value is an object (and not null)
        if (typeof value === 'object' && value !== null) {
          // Uncomment below to exclude arrays from the count
          // if (!Array.isArray(value)) {
            totalCount++;
          // }
        }
        // Recursively check nested properties/elements
        traverse(value);
      });
    }
  }

  // Start traversing from the top-level object
  traverse(targetObj);
  return totalCount;
}

// Usage example
const totalObjects = countObjectProperties(Obj);
console.log(`Total object-type properties: ${totalObjects}`);

Key Notes: #

• Exclude null: Always include s !== null in your check—this avoids counting null values which JavaScript incorrectly labels as objects.
• Exclude Arrays: If you don't want arrays to be counted (since typeof [] also returns 'object'), uncomment the !Array.isArray(value) condition in the recursive function.
• Flexibility: The recursive approach works for any nested structure, whether it's 3 layers deep or 10.

内容的提问来源于stack exchange，提问作者Jose Peres