fontoxpath

fontoxpath

A minimalistic XPath 3.1 selector engine for (XML) nodes.

Demo page

How to use

let { evaluateXPathToBoolean, domFacade } = require('fontoxpath');
let documentNode = ...;
console.log(evaluateXPathToBoolean('true()', documentNode, domFacade)); // => true

FontoXPath supplies a number of API functions:

• domFacade: A wrapper to the DOM. All DOM accesses should go through here
• A number of evaluateXPath.* functions:
  • evaluateXPath(xpath: string, contextNode: Node, domFacade: DomFacade?, variables: Object={}, returnType: number) => *
  • evaluateXPathToNodes(xpath: string, contextNode: Node, domFacade: DomFacade?, variables: Object={}, options: {namespaceResolver: function(string):string?}) => Node[]
  • evaluateXPathToFirstNode(xpath: string, contextNode: Node, domFacade: DomFacade?, variables: Object={}, options: {namespaceResolver: function(string):string?}) => Node
  • evaluateXPathToBoolean(xpath: string, contextNode: Node, domFacade: DomFacade?, variables: Object={}, options: {namespaceResolver: function(string):string?}) => boolean
  • evaluateXPathToNumber(xpath: string, contextNode: Node, domFacade: DomFacade?, variables: Object={}, options: {namespaceResolver: function(string):string?}) => number
  • evaluateXPathToNumbers(xpath: string, contextNode: Node, domFacade: DomFacade?, variables: Object={}, options: {namespaceResolver: function(string):string?}) => number[]
• precompileXPath(xpath: string) => Promise<string>
  • A no-op on systems without indexedDB
• registerCustomXPathFunction(name: string, signature: string[], returnType: string, callback: function)
  • Can be used to register custom functions. They are registered globally.

Features

Note that this engine assumes XPath 1.0 compatibility mode turned off.

Not all XPath 3.1 functions are implemented yet. We accept pull requests for missing features.

The following features are unavailable, but will be implemented at some point in time (and even sooner if you can help!):

• DateTime related functions
• Collation related functions (fn:compare#3)
• The ? lookup operator for maps and arrays
• XML parsing

The following features are available:

• maps / arrays
• variables using let
• The ! bang operator
• Most built in dataTypes

For all available features, see the unit tests.

Contribution

To recompile the parser, run the following:

npm install
npm run build [--skip_parser] [--skip_closure]

Note: Rebuilding the closure build depends on Java.

To run the tests, run

npm run test [--ci_mode] [--integration_tests]

The integration tests run all tests only using the externally public API, using the closure build.

QT3 tests

A basic test runner for the QT3 tests can be used by running npm run test --qt3 --integration_tests. For this, a recent version of the QT3 test set should be present at test/assets/.