gonzales-pe

What is gonzales-pe?

The gonzales-pe npm package is a CSS parser that can parse CSS, SCSS, LESS, and other CSS-like syntaxes. It is useful for tasks such as linting, formatting, and transforming stylesheets.

What are gonzales-pe's main functionalities?

Parsing CSS

This feature allows you to parse CSS code into an Abstract Syntax Tree (AST). The code sample demonstrates how to parse a simple CSS string and convert it into a JSON representation of the AST.

const gonzales = require('gonzales-pe');
const ast = gonzales.parse('.class { color: red; }', { syntax: 'css' });
console.log(ast.toJson());

Parsing SCSS

This feature allows you to parse SCSS code into an AST. The code sample shows how to parse a simple SCSS string and convert it into a JSON representation of the AST.

const gonzales = require('gonzales-pe');
const ast = gonzales.parse('.class { color: red; }', { syntax: 'scss' });
console.log(ast.toJson());

Parsing LESS

This feature allows you to parse LESS code into an AST. The code sample demonstrates how to parse a simple LESS string and convert it into a JSON representation of the AST.

const gonzales = require('gonzales-pe');
const ast = gonzales.parse('.class { color: red; }', { syntax: 'less' });
console.log(ast.toJson());

Transforming AST

This feature allows you to traverse and transform the AST. The code sample shows how to change the color property from 'red' to 'blue' in a CSS AST.

const gonzales = require('gonzales-pe');
let ast = gonzales.parse('.class { color: red; }', { syntax: 'css' });
ast.traverse(function(node) {
  if (node.type === 'declaration' && node.content[0].content === 'color') {
    node.content[1].content = 'blue';
  }
});
console.log(ast.toString());

Other packages similar to gonzales-pe

postcss

PostCSS is a tool for transforming CSS with JavaScript plugins. It is more versatile and has a larger ecosystem of plugins compared to gonzales-pe. PostCSS can be used for linting, autoprefixing, and many other CSS transformations.

csstree

CSSTree is a tool for working with CSS, including parsing, generating, and analyzing CSS. It provides a more detailed and accurate AST compared to gonzales-pe and includes utilities for working with the AST.

rework

Rework is a plugin framework for CSS preprocessing. It allows you to transform CSS with plugins, similar to PostCSS. Rework is simpler and less feature-rich compared to PostCSS but can be easier to use for basic transformations.

README

Gonzales PE @3.2.0

[] (https://travis-ci.org/tonyganch/gonzales-pe)

Gonzales PE is a CSS parser which plays nicely with preprocessors.
Currently those are supported: SCSS, Sass, LESS.

Install

(1) To install command-line tool globally:

npm install -g gonzales-pe@3.2.0

(2) To install parser as a project dependency:

npm install --save gonzales-pe@3.2.0

(3) If for some reason you want to build files yourself:

# Clone the repo.
git clone [e-mail]:tonyganch/gonzales-pe.git
# Go to `3.0` branch.
git checkout 3.0
# Install project dependencies.
npm install
# Install git hooks and build files.
npm run init

API

Basically there are a few things you can do:

1. parse css string and get a parse tree in return;
2. modify tree nodes;
3. remove tree nodes;
4. add new nodes to the tree;
5. convert modified tree back to a string.

In examples below I assume that gonzales is a parser module and parseTree is some parsed css:

let gonzales = require('gonzales-pe');
let parseTree = gonzales.parse(css);

gonzales.createNode(options)

Description

Creates a new node. Useful when you need to add something to a tree.

Parameters

{Object}	options	Options to pass to a `Node` constructor.

Returns

{Object}

A new node.

Examples

let css = 'a {color: tomato}';
let parseTree = gonzales.parse(css);
let node = gonzales.createNode({ type: 'animal', content: 'panda' });
parseTree.content.push(node);

gonzales.parse(css[, options])

Description

Parses a css string.

Parameters

{string}	css	A string to parse.
{Object=}	options	Optional. Additional options: {string} syntax — any of the following: css, less, sass, scss. Default one is css. {string} context — root node's type. For a list of available values see "Node types". Default one is stylesheet. {number} tabSize — size of a tab character in spaces. Default one is 1.

Returns

{Object}

Parse tree.

Examples

let css = 'a {color: tomato}';
let parseTree = gonzales.parse(css);

let less = 'a {$color: tomato}';
let parseTree = gonzales.parse(less, {syntax: 'less'});

let less = '$color: tomato';
let parseTree = gonzales.parse(less, {syntax: 'less', rule: 'declaration'});

parseTree.contains(type)

Description

Checks whether there is a child node of given type.

Parameters

{string}

type

Node type we're looking for. For a list of available values see "Node types".

Returns

{boolean}

true if a tree contains a child node of a given type, false otherwise.

Examples

if (parseTree.contains('space')) {
  doSomething();
}

parseTree.content

Returns

{string|Array}

Node's content (child nodes or a string).

parseTree.eachFor([type, ]callback)

Description

Calls a function for every child node in tree. If type parameter is passed, calls a function only for child nodes of a given type. The main difference from parseTree.forEach() is that this method loops through node list from the end to beginning.

Parameters

{string=}	type	Optional. A node type by which to filter child nodes before applying a callback function. For a list of available values see "Node types".
{Function}	callback	Function to call for every child node. Accepts following parameters: {Object} — a child node; {number} — index of the child node in node list; {Object} — parent node (equals to parseTree).

Examples

parseTree.eachFor(function(childNode) {
  doSomething(childNode);
});

// Remove all child spaces.
parseTree.eachFor('space', function(spaceNode, i) {
  parseTree.removeChild(i);
});

parseTree.end

Returns

{Object}

End position of the node. Contains following info: {number} line — last symbol's line number (1-based index); {number} column — last symbol's column number (1-based index).

parseTree.first([type])

Description

Gets the first child node. If type parameter is passed, gets the fisrt child node of a given type. If no node has been found, returns null.

Parameters

{string=}

type

Optional. Node type to look for. For a list of available values see "Node types".

Returns

{?Object}

A node.

Examples

let node = parseTree.first();
node.content = 'panda';

let node = parseTree.first('multilineComment');
node.content = 'panda';

parseTree.forEach([type, ]callback)

Description

Calls a function for every child node in tree. If type parameter is passed, calls a function only for child nodes of a given type. The main difference from parseTree.eachFor() is that this method loops through node list from the beginnig to end.

Parameters

{string=}	type	Optional. A node type by which to filter child nodes before applying a callback function. For a list of available values see "Node types".
{Function}	callback	Function to call for every child node. Accepts following parameters: {Object} — a child node; {number} — index of the child node in node list; {Object} — parent node (equals to parseTree).

Examples

parseTree.forEach(function(childNode) {
  doSomething();
});

parseTree.forEach('space', function(spaceNode) {
  doSomething();
});

parseTree.get(index)

Description

Gets nth child of the parseTree. If no node has been found, returns null.

Parameters

{number}

index

Index number of node which we're looking for.

Returns

{?Object}

A node.

Examples

var node = parseTree.get(2);
doSomething(node);

parseTree.insert(index, node)

Description

Inserts a node to a given position in parseTree.

Parameters

{number}	index	Index of position where to insert the node.
{Object}	node	A node to insert.

Examples

let node = gonzales.createNode({type: 'animal', content: 'panda'});
parseTree.insert(2, node);

parseTree.is(type)

Description

Checks whether the node is of given type.

Parameters

{string}

type

A node type against which to check type of parseTree. For a list of available values see "Node types".

Returns

{boolean}

true if types are equal, false otherwise.

Examples

if (node.is('space')) {
  node.content = '';
}

parseTree.last(type)

Gets the last child node. If type parameter is passed, gets the last child node of a given type. If no node has been found, returns null.

Parameters

{string=}

type

Optional. Node type to look for. For a list of available values see "Node types".

Returns

{?Object}

A node.

Examples

let node = parseTree.last();
node.content = 'panda';

let node = parseTree.last('multilineComment');
node.content = 'panda';

parseTree.length

Returns

{number}

Number of child nodes.

parseTree.removeChild(index)

Description

Removes a child node at a given position.

Parameters

{number}

index

Index of a child node we need to remove.

Returns

{Object}

Removed node.

##### Examples

// Swap nodes.
var node = parseTree.removeChild(1);
parseTree.insert(0, node);

parseTree.start

Returns

{Object}

Start position of the node. Contains following info: {number} line — first symbol's line number (1-based index); {number} column — first symbol's column number (1-based index).

parseTree.syntax

Returns

{string}

Syntax of original parsed string.

parseTree.toJson()

Description

Converts parse tree to JSON. Useful for printing.

Returns

{Object}

Parse tree in JSON

parseTree.toString()

Description

Converts parse tree back to string according to original syntax.

Returns

{string}

A compiled string.

Examples

let css = parseTree.toString();

parseTree.traverse(callback)

Description

Calls the function for every node in a tree including parseTree itself.

Parameters

{Function}

callback

Function to apply to every node. Accepts following parameters: {Object} — a node to which we apply callback; {number} — node's index number inside its parent; {Object} — a node's parent; {number} — node's nesting level relative to its parent.

Examples

parseTree.traverse(function(node, index, parent) {
  if (node.is('multilineComment')) {
    parent.removeChild(index);
  } else if (node.is('space')) {
    node.content = ' ';
  }
});

parseTree.traverseByType(type, callback)

Description

This method should be called for a root node, because calling it for a child will be more time consuming.
Calls the function for every node of a given type. This means not just child nodes, but grandchilds and so on.

Parameters

{string}	type	Node type. For a list of available values please see "Node types".
{Function}	callback	Function to apply to every node of a given type. Accepts following parameters: {Object} — a node to which we apply callback; {number} — node's index number inside its parent; {Object} — a node's parent.

Examples

// Remove all comments.
parseTree.traverseByType('multilineComment', function(node, nodeData) {
  parent.removeChild(index);
});

parseTree.traverseByTypes(types, callback)

Description

This method should be called for a root node, because calling it for a child will be more time consuming.
Calls the function for every node of given types. This means not just child nodes, but grandchilds and so on.

Parameters

{Array.string}	types	List of node types. For a list of available values please see "Node types".
{Function}	callback	Function to apply to every node of given types. Accepts following parameters: {Object} — a node to which we apply callback; {number} — node's index number inside its parent; {Object} — a node's parent.

Examples

// Remove all comments and spaces.
let types = ['multilineComment', 'space'];
parseTree.traverseByTypes(types, function(node, index, parent) {
  parent.removeChild(index);
});

parseTree.type

Returns

{string}

Node type. For a list of available values see "Node types".

Test

To run tests:

npm test

This command will build library files from sources and run tests on all files in syntax directories.

Every test has 3 files: source stylesheet, expected parse tree and expected string compiled back from parse tree to css.

If some tests fail, you can find information in test logs:

• log/test.log contains all information from stdout;
• log/expected.txt contains only expected text;
• log/result.txt contains only result text.

The last two are made for your convenience: you can use any diff app to see the defference between them.

If you want to test one specific string or get a general idea of how Gonzales works, you can use test/ast.js file.
Simply change the first two strings (css and syntax vars) and run:

node test/single-test.js

Report

If you find a bug or want to add a feature, welcome to Issues.

If you are shy but have a question, feel free to drop me a line.

Changelog

19.10.2015, version 3.2.0

Node types

:star: Added new node type: parentSelectorExtension.

Parsing rules

:green_apple: Fixed parsing of parent selectors with extensions, like &__element or &--modifier.