primefaces/primeng

Bug: Hour increment/decrement buttons in DatePicker not working correctly

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#19557 opened on Apr 30, 2026

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Type: Buggood first issue

Description

Describe the bug

Create a DatePicker control and set the minDate hour to 9. In the DatePicker dropdown, when clicking the hour increment (up) button, the numbers display correctly and cycle as expected. However, when clicking the hour decrement (down) button, the values only loop between 9, 10, and 11 instead of cycling through all hours.

Pull Request Link

No response

Reason for not contributing a PR

  • Lack of time
  • Unsure how to implement the fix/feature
  • Difficulty understanding the codebase
  • Other

Other Reason

No response

Reproducer

https://stackblitz.com/edit/stackblitz-starters-gmn6zbuj?file=src%2Fmain.ts,src%2Findex.html,package.json

Environment

Windows 11, chrome 147

Angular version

21

PrimeNG version

v19 (LTS Only)

Node version

No response

Browser(s)

chrome 147

Steps to reproduce the behavior

  1. Open the StackBlitz website.
  2. Click on the DatePicker dropdown.
  3. Click the hour down button.

You will notice that the behavior is clearly different from the up button.

Expected behavior

When clicking the hour up and down buttons, the behavior should be consistent.

Contributor guide

Tech stack
typescriptangularhtmlcss
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic knowledge of AngularFamiliarity with PrimeNG componentsUnderstanding of DatePicker logic
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75
Research direction
Review the StackBlitz reproducer to understand the bug. Look at the hour decrement logic in the PrimeNG DatePicker component, likely in p datepicker.ts or the template. The issue is that the down button cycles only between 9, 10, and 11 instead of all hours. Check the loop implementation for the down button and compare with the up button to identify the off by one or logic error. No linked PRs or comments yet.