JarCastingGonzales PE @dev
Gonzales PE is a CSS parser which plays nicely with preprocessors.
Currently those are supported: SCSS, Sass, LESS.
Try out Gonzales PE online: Gonzales PE Playground.
Install
(1) To install command-line tool globally:
npm install -g git://github.com/tonyganch/gonzales-pe.git#dev
(2) To install parser as a project dependency:
npm install --save git://github.com/tonyganch/gonzales-pe.git#dev
(3) If for some reason you want to build files yourself:
# Clone the repo.
git clone [email protected]:tonyganch/gonzales-pe.git
# Go to dev branch.
git checkout dev
# Install project dependencies.
npm install
# Install git hooks and build files.
npm run init
API
Basically there are a few things you can do:
- parse css string and get a parse tree in return;
- modify tree nodes;
- remove tree nodes;
- add new nodes to the tree;
- convert modified tree back to a string.
The different type of tree nodes can be found in docs/node-types.md.
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:
|
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:
|
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:
|
parseTree.first([type])
Description
Gets the first child node. If type parameter is passed, gets the first 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:
|
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. |
// Swap nodes.
var node = parseTree.removeChild(1);
parseTree.insert(0, node);
parseTree.start
Returns
| {Object} | Start position of the node. Contains following info:
|
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:
|
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:
|
Examples
// Remove all comments.
parseTree.traverseByType('multilineComment', function(node, index, parent) {
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:
|
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.logcontains all information from stdout;log/expected.txtcontains only expected text;log/result.txtcontains 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.