Array Length returns 0

by

Only numeric indices affect the .length of an Array.

Other named properties are allowed, but they aren’t the typical use for an Array object. By using "", you’re creating a non-numeric property on the object. You can access it like this:

errors[""];

But you can’t get to it with the typical Array methods.

For named properties, you’d typically use an Object instead. Either way, you can get a count of the number of own, enumerable properties (including numeric indices) by using Object.keys().

Object.keys(errors).length;

More Related Contents:

  1. Array.prototype.fill() with object passes reference and not new instance
  2. JavaScript: Difference between .forEach() and .map()
  3. Why can I add named properties to an array as if it were an object?
  4. How to extend an existing JavaScript array with another array, without creating a new array
  5. Is the order of elements in a JSON list preserved?
  6. JavaScript: How to join / combine two arrays to concatenate into one array?
  7. Maximum size of an Array in Javascript
  8. Sum JavaScript object propertyA values with the same object propertyB in an array of objects
  9. Merge 2 arrays of objects
  10. Convert string with commas to array
  11. How might I extract the property values of a JavaScript object into an array?
  12. Sampling a random subset from an array
  13. Create object from array
  14. Comparing two arrays of objects, and exclude the elements who match values into new array in JS
  15. How to check if a string array contains one string in JavaScript? [duplicate]
  16. Count duplicates within an Array of Objects
  17. MongoDB select where in array of _id?
  18. Search array of objects for entry matching variable and check if it matches other fields
  19. How can I perform an inner join with two object arrays in JavaScript?
  20. How to get the first element of an array?
  21. Javascript 2d array indexOf
  22. How to merge each object within arrays by index?
  23. Unexpected comma using map()
  24. Counting occurrences of particular property value in array of objects [duplicate]
  25. Convert js Array() to JSon object for use with JQuery .ajax
  26. How to find a value in an array of objects in JavaScript?
  27. Javascript: hiding prototype methods in for loop?
  28. If I set only a high index in an array, does it waste memory?
  29. looping through arrays of arrays
  30. Why is .forEach returning undefined?

Leave a Comment