Theme Check ✅ - A linter for Themes
Think RuboCop, or eslint, but for Shopify themes.
Theme Check is a command line tool that helps you follow Shopify Themes & Liquid best practices by analyzing the Liquid & JSON inside your theme.
Theme Check is also available inside some code editors.
Supported Checks
Theme Check currently checks for the following:
✅ Liquid syntax errors
✅ JSON syntax errors
✅ Missing snippet & section templates
✅ Unused {% assign ... %}
✅ Unused snippet templates
✅ Template length
✅ Deprecated tags
✅ Unknown tags
✅ Unknown filters
✅ Missing {{ content_for_* }}
in theme.liquid
✅ Excessive nesting of snippets
✅ Missing or extra spaces inside {% ... %}
and {{ ... }}
✅ Missing default locale file
✅ Unmatching translation keys in locale files
✅ Using unknown translation keys in {{ 'missing_key' | t }}
✅ Using several {% ... %}
instead of {% liquid ... %}
✅ Undefined objects
✅ Deprecated filters
✅ Missing theme-check-enable
comment
As well as checks that prevent easy to spot performance problems:
✅ Use of parser-blocking JavaScript
✅ Use of non-Shopify domains for assets
✅ Missing width and height attributes on img
tags
✅ Too much JavaScript
✅ Too much CSS
For detailed descriptions and configuration options, take a look at the complete list.
With more to come! Suggestions welcome (create an issue).
Requirements
- Ruby 2.7+
Installation
Theme Check is available through Homebrew or RubyGems.
Homebrew
You’ll need to run brew tap
first to add Shopify’s third-party repositories to Homebrew.
brew tap shopify/shopify
brew install theme-check
RubyGems
gem install theme-check
Usage
theme-check /path/to/your/theme
# or from /path/to/your/theme
theme-check
Run theme-check --help
to get full usage.
Configuration
Add a .theme-check.yml
file at the root of your theme to configure:
# If your theme is not using the supported directory structure, provide the root path
# where to find the `templates/`, `sections/`, `snippets/` directories as they would
# be uploaded to Shopify.
root: dist
# It is possible to extend theme-check with custom checks
require:
- ./path/to/my_custom_check.rb
TemplateLength:
# Disable some checks
enabled: false
# Or configure options
max_length: 300
# Or ignore certain paths
ignore:
- snippets/icon-*
# Or change the severity (error|suggestion|style)
severity: suggestion
# Enable a custom check
MyCustomCheck
enabled: true
See config/default.yml for available options & defaults.
Disable checks with comments
Use Liquid comments to disable and re-enable all checks for a section of your template:
{% # theme-check-disable %}
{% assign x = 1 %}
{% # theme-check-enable %}
Disable a specific check by including it in the comment:
{% # theme-check-disable UnusedAssign %}
{% assign x = 1 %}
{% # theme-check-enable UnusedAssign %}
Disable multiple checks by including them as a comma-separated list:
{% # theme-check-disable UnusedAssign,SpaceInsideBraces %}
{%assign x = 1%}
{% # theme-check-enable UnusedAssign,SpaceInsideBraces %}
Disable checks for the entire document by placing the comment on the first line:
{% # theme-check-disable SpaceInsideBraces %}
{%assign x = 1%}
--fail-level
Exit Code and Use the --fail-level
(default: error
) flag to configure the exit code of theme-check. Useful in CI scenarios.
Example:
# Make CI fail on styles warnings, suggestions, and errors
theme-check --fail-level style path_to_theme
# Make CI fail on suggestions, and errors
theme-check --fail-level suggestion path_to_theme
# Make CI fail on errors
theme-check path_to_theme
There are three fail levels:
error
suggestion
style
Exit code meanings:
- 0: Success!
- 1: Your code doesn't pass the checks
- 2: There's a bug in theme-check
If you would like to change the severity of a check, you can do so with the severity
attribute. Example:
DeprecateLazysizes:
enabled: true
severity: error
Language Server Configurations
themeCheck.checkOnOpen
(default:true
) makes it so theme check runs on file open.themeCheck.checkOnChange
(default:true
) makes it so theme check runs on file change.themeCheck.checkOnSave
(default:true
) makes it so theme check runs on file save.themeCheck.onlySingleFileChecks
(default:false
) makes it so we only check the opened files and disable "whole theme" checks (e.g. UnusedSnippet, TranslationKeyExists)
In VS Code, these can be set directly in your settings.json
.
Contributing
For guidance on contributing, refer to this doc