Bug Tracker

Ticket #10977 (closed bug: fixed)

Opened 4 years ago

Last modified 3 years ago

Incorrect documentation for the index method?

Reported by: AbeMiessler@… Owned by: rwaldron
Priority: high Milestone: None
Component: traversing Version: 1.7.1
Keywords: Cc:
Blocking: Blocked by:


You have the following documentation for index with no parameters:

If no argument is passed to the .index() method, the return value is an integer indicating the position of the first element within the jQuery object relative to its sibling elements.

But if you run this jQuery:


Against this HTML:

    <li class="selected">First Item</li>
    <li class="disabled">Second Item</li>
    <li class="separator">Third Item</li>
    <li>Fourth Item</li>

It returns 3 instead of 0. You can see that the selector will find two elements (the first and last LI), but it returns the index of the last element, when your documentation says it will return the index of the first.

Can be seen in this fiddle:  http://jsfiddle.net/Zf9Vv/

Change History

comment:1 Changed 4 years ago by john.papaioannou@…

I have tested this snippet in multiple jQuery versions, and discovered that it is a regression introduced in 1.6.3. Please see  this question on StackOverflow (and specifically,  this answer) that pinpoints the guilty code.

comment:2 Changed 4 years ago by anonymous

Culprit:  https://github.com/jquery/jquery/commit/9a96af1d59cc6a10b89b6f2489b04871a9c1c7fa#src/traversing.js

Fix, add first()

return ( this[0] && this[0].parentNode ) ? this.first().prevAll().length : -1;

comment:3 Changed 4 years ago by rwaldron

  • Owner set to rwaldron
  • Priority changed from undecided to high
  • Status changed from new to assigned
  • Component changed from unfiled to traversing

comment:4 Changed 4 years ago by addyosmani

  • Keywords needsdocs added

comment:5 Changed 3 years ago by mikesherov

  • Keywords needsdocs removed
  • Status changed from assigned to closed
  • Resolution set to notabug

comment:6 Changed 3 years ago by mikesherov

  • Status changed from closed to reopened
  • Resolution notabug deleted

comment:7 Changed 3 years ago by mikesherov

  • Status changed from reopened to open

comment:8 Changed 3 years ago by MORGAN

  • Status changed from open to closed
  • Resolution set to fixed

Return correct index for no-arg index() calls. Fixes #10977. Closes gh-971

Changeset: 4bb46f413a0e2f6933013b26d2aceddca6cf03f1

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