TypeScript helper functions to narrow the type of object to a Node descendant
npm install @xmldom/is-dom-node!Build Status
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@xmldom/is-dom-node is a versatile TypeScript library designed to provide robust utility functions for working with DOM nodes. Whether you're developing for the browser or dealing with XML in NodeJS, this library offers a comprehensive set of functions for checking and asserting various types of DOM nodes. It's particularly useful when working with NodeJS libraries like xpath and @xmldom/xmldom, as it can validate the objects returned by these libraries.
``shell`
npm install @xmldom/is-dom-node
Import the library and use it as follows:
`javascript
import * as isDomNode from "@xmldom/is-dom-node";
const element = document.createElement("div");
const result = isDomNode.isElementNode(element); // Output: true
`
`typescript
import * as isDomNode from "@xmldom/is-dom-node";
function handleNode(node: Node) {
if (isDomNode.isElementNode(node)) {
// TypeScript now knows node is an Elementnode
console.log(node.tagName);
} else if (isDomNode.isTextNode(node)) {
// TypeScript now knows is a Text nodenode
console.log(node.wholeText);
} else {
try {
// Assert that the node is a Comment node
isDomNode.assertIsCommentNode(node);
// TypeScript now knows is a Comment node`
console.log(node.nodeValue);
} catch (error) {
console.error("Node is not a Comment node:", error);
}
}
}
The API consists of two main types of functions:
These functions return a boolean value indicating whether the given object meets certain criteria:
- isNodeLike: Checks if a given value resembles a DOM node.isArrayOfNodes
- : Checks if the given value is an array of DOM nodes.isElementNode
- , isAttributeNode, isTextNode, etc.: Check for specific types of DOM nodes.
These functions assert that a given object meets certain criteria and throw an error if it doesn't:
- assertIsNodeLike: Asserts that a given value is a DOM node.assertIsArrayOfNodes
- : Asserts that the given value is an array of DOM nodes.assertIsElementNode
- , assertIsAttributeNode, assertIsTextNode, etc.: Assert for specific types of DOM nodes.
Both the is... and assertIs... functions can be used for TypeScript type narrowing. After a successful check or assertion, TypeScript will recognize the specific type of the DOM node, allowing for more robust and error-free code.
- Lightweight
- Written in TypeScript
- Comprehensive tests
- Compatible with NodeJS XML libraries like xpath and @xmldom/xmldom`
Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests.
This project is licensed under the MIT License - see the LICENSE.md file for details.