javascript surprising array comparison

by

The array is converted to a string, which comes down to .join(), which in turn joins the elements with a comma (,) as delimiter.

"-1,1" < "0,0" === true

because the character code of - (45) is smaller than the character code of 0 (48).

On the other hand,

"-2" < "-1" === false

because the second character codes are compared (the first are both -, so that doesn’t give a result yet), and the character code for 2 (50) is bigger than the character code of 1 (49), so this yields false.

It comes down to a lexographical sorting (i.e. by character codes) and not a numerical one, even if the elements are numbers (because of the string coercion).

Basically comparing arrays is not recommended. It is implicitly defined as string comparison, but this can yield surprising results.

More Related Contents:

  1. Sort array of objects by string property value
  2. Comparing Arrays of Objects in JavaScript
  3. How to check identical array in most efficient way? [duplicate]
  4. Deep comparison of objects/arrays [duplicate]
  5. Does an array contain a specific item? [duplicate]
  6. How to get the difference between two arrays of objects in JavaScript
  7. How to delete an item from state array?
  8. JavaScript, Node.js: is Array.forEach asynchronous?
  9. Completely removing duplicate items from an array
  10. How to remove element from an array in JavaScript?
  11. How to flatten nested array in javascript? [duplicate]
  12. sort Javascript array by two numeric fields
  13. Merge duplicate objects in array of objects
  14. Create object from array
  15. How to generate range of numbers from 0 to n in ES2015 only?
  16. Sorting on a custom order
  17. How do I extract even elements of an Array?
  18. How does (A == B == C) comparison work in JavaScript?
  19. How to store a byte array in Javascript
  20. Replace element at specific position in an array without mutating it
  21. push() a two-dimensional array
  22. Javascript array search and remove string?
  23. TypeScript enum to object array
  24. Using lodash to compare jagged arrays (items existence without order)
  25. Access object property in array of objects
  26. Javascript – insert an array inside another array
  27. split an array into two based on a index in javascript
  28. Using reduce() to find min and max values?
  29. How to sum elements at the same index in array of arrays into a single array?
  30. Map/Set to maintain unique array of arrays, Javascript

Leave a Comment