excalidraw/excalidraw

Improve Feedback: Display Error Message for Invalid Hexadecimal Color Codes

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#9527 opened on May 14, 2025

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UX/UIenhancementgood first issue

Description

Description

Currently, Excalidraw accepts some invalid or malformed hexadecimal color values in the color input field without providing any visual or textual feedback to the user. This may cause confusion as users may not realize why the color hasn’t changed.

Steps to Reproduce

  1. Open Excalidraw.
  2. Select the pencil tool (or any tool that allows color selection).
  3. Open the custom color input field (hex code).
  4. Enter the following invalid values one at a time:
  • 123456789 → more than 8 characters
  • 1 → only 1 digit
  • 12 → only 2 digits
  • 12345 → 5 digits
  • 1234567 → 7 digits
  • zzzzzz → contains invalid hexadecimal characters
  • blue → non-hex text input

Expected Behavior

A clear and visible error message should appear when an invalid hexadecimal value is entered, such as:

  • Error: Hex code must be 3, 4, 6, or 8 characters (excluding #)
  • Error: Invalid characters in hex code
  • Error: Not a valid hex color

Actual Behavior

The input is ignored silently and the pencil color remains unchanged. No error or feedback is shown to the user.

Why This Matters

  • Improves usability by helping users understand why their input didn’t work.
  • Prevents frustration or confusion when using custom colors.
  • Follows good UX practices for input validation and error feedback.

Suggested Fix

Implement front-end validation in the color input field and display an error tooltip or inline message when an invalid value is detected.

Contributor guide

Tech stack
typescriptreact
Domain
frontend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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
React component basicsTypeScriptHex color validationExcalidraw codebase structure
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
90
Research direction
Look for the color input component in Excalidraw (likely in src/components/ColorPicker or similar). Understand the current hex input handling (e.g., onChange). Implement validation for hex length (3,4,6,8 chars) and valid characters, then display an error message via tooltip or inline text. Follow existing error patterns in the codebase. Ensure error resets on valid input.