The Adblock Plus coding style is based on others. Our rules (both general and language specific) always overrule referenced style guides. The language specific sections overrule the general section.
Consistency is most important: Be consistent within functions, files, modules and projects. Making existing code conform with this style guide is fine, but it should happen in dedicated commits, preferably for a whole module or project at once.
- Follow the Mozilla Coding Style's general practices and its naming and formatting rules.
- All files should have a license header, but no mode line comments.
- Newline at end of file, otherwise no trailing whitespace.
- Lines can be longer than the limit, if limiting line length would hurt readability in a particular case.
- Opening braces always go on their own line.
- No hungarian notation, no special variable name prefixes or suffixes denoting type or scope. All variable names start with a lower case letter.
- Don't comment code out, delete it.
- Don't add TODO comments, create an issue and reference it in a comment instead.
- Always optimize PNG images using ZopfliPNG.
- Always use strict mode.
- When splitting overlong expressions into multiple lines the joining binary operators should be left at the end of the line, before the linebreak. This does not apply to member access operators, such as
.which should be placed on the following line.
- When an
elsestatement or a loop spans over more than one line always enclose it with braces.
- In classes, prefix private functions with a single underscore to make them pseudo-private.
- Don't add any spaces immediately after opening, or before closing, an object or array literal.
- Always use block-scoping (
const), except when sharing global variables between scripts cannot be avoided.
constfor constant expressions that could as well have been inlined (e.g. static parameters, imported modules, etc.).
- Use the arrow function syntax when passing anonymous functions that don't require the binding of their own
- Use the method definition shorthand syntax when defining methods on an object.
- When iterating over arrays in the canonical order use the new
for..ofsyntax if the loop index isn't required. (Rather than using
- Use the
Setobjects, rather than misusing plain objects, when you need a hash table.
- Run ESLint with the eslint-config-eyeo configuration and fix any warning.
HTML and CSS
- Follow the Google HTML/CSS Style Guide.
- Use double over single quotation marks.
- Don't omit optional HTML tags.
- CSS color values should be specified in hexadecimal where possible.
- CSS shorthand properties usage is optional.
- CSS rule declaration order should follow the WordPress CSS Coding Standards.
- Don't omit the optional leading 0 for decimal numbers.
- CSS declaration blocks with a single selector and a single rule can be written in a single line.
- Follow PEP-8 and the recommendations in the offical Python documentation.
- Make the code compatible with both Python 2.7 and Python 3.5+ (see this guide). Use __future__ imports to address syntactic differences but avoid six, python-future, etc. to not introduce additional dependencies.
- Write string literals so that they match the behaviour of
ascii(), i.e. use single quotes except to avoid escaping of embedded quotes and use
\uescapes for non-ascii characters but don't prefix strings with
u. For docstrings, however, follow PEP-257.
- In modules, prefix private functions and variables with a single underscore.
- Use the
+operator when concatenating exactly two strings, use the
format()method for more complex string formatting, use the
join()method when concatenating pre-existing sequences.
- Use tuples for data that have structure, use lists for data that have order.
- Don't override builtins except for non-essential builtins and
filewhich is superfluos in modern code as well.
- Use list comprehensions or generator expressions instead of calling
filter()with a lambda function.
re.match()to avoid confusion about implied beginning of the string but not the ending.
- Run flake8 with following extensions and fix all reported errors:
- Write tests and have them run along flake8 using tox.
- Follow the Mozilla Coding Style's Java practices.
- Imports should be organised consistently per file, we don't use global rules.
- Follow the Mozilla Coding Style's C++ practices.
- Indent namespace bodies.
- Avoid manual memory management: Use references and values when possible, smart pointers when necessary, raw pointers only for weak references.
- Don't use C-style casts unless its exact semantics are required.
- We tend to use anonymous namespaces instead of static.
- Follow Apple's conventions.
- Follow the Puppet Style Guide.
- Opening braces don't go on their own line.
- Arrows should not be aligned.