@xml-tools/ast
v5.0.5
Published
XML Ast and Utilities
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@xml-tools/ast
Utilities for building and traversing an XML Abstract Syntax Tree ([AST][ast]).
There are two things which distinguish this AST from most others ASTs:
- This AST can represent a partially valid XML, in practice this means virtually all properties on the AST are optional and may have undefined values.
- This AST contains additional syntactic information to enable additional linting & formatting flows, for example:
- the original position and value of an attribute's value (including the quotes).
- The original positions and values of an XMLElement's open/close names.
The input for constructing the AST is a CST which is created by the @xml-tools/parser package.
The AST structure is used as part of the input for the @xml-tools/content-assist APIs.
Installation
With npm:
npm install @xml-tools/ast
With Yarn
yarn add @xml-tools/ast
Usage
Please see the TypeScript Definitions for full API details.
A simple usage example:
const { parse } = require("@xml-tools/parser");
const { buildAst, accept } = require("@xml-tools/ast");
const xmlText = `<note>
<to>Bill</to>
<from>Tim</from>
</note>
`;
const { cst, tokenVector } = parse(xmlText);
const xmlDocAst = buildAst(cst, tokenVector);
console.log(xmlDocAst.rootElement.name); // -> note
// A Visitor allows us to invoke actions on the XML ASTNodes without worrying about
// The XML AST structure / traversal method.
const printVisitor = {
// Will be invoked once for each Element node in the AST.
visitXMLElement: function (node) {
console.log(node.name);
},
// An XML AST Visitor may have other methods as well, see the api.d.ts file/
};
// Invoking the Visitor
accept(xmlDocAst, printVisitor); // -> note, Bill, Tim
Support
Please open issues on github.
Contributing
See CONTRIBUTING.md.