speech-rule-engine/js/common/xpath_util.js

A standalone speech rule engine for XML structures, based on the original engine from ChromeVox.

import { Engine } from './engine.js';
import * as EngineConst from '../common/engine_const.js';
import { SystemExternal } from './system_external.js';
export const xpath = SystemExternal.xpath;
const nameSpaces = {
    xhtml: 'http://www.w3.org/1999/xhtml',
    mathml: 'http://www.w3.org/1998/Math/MathML',
    mml: 'http://www.w3.org/1998/Math/MathML',
    svg: 'http://www.w3.org/2000/svg'
};
export function resolveNameSpace(prefix) {
    return nameSpaces[prefix] || null;
}
class Resolver {
    constructor() {
        this.lookupNamespaceURI = resolveNameSpace;
    }
}
function evaluateXpath(expression, rootNode, type) {
    return xpath.evaluate(expression, rootNode, new Resolver(), type, null);
}
export function evalXPath(expression, rootNode) {
    let iterator;
    try {
        iterator = evaluateXpath(expression, rootNode, xpath.result.ORDERED_NODE_ITERATOR_TYPE);
    }
    catch (_err) {
        return [];
    }
    const results = [];
    for (let xpathNode = iterator.iterateNext(); xpathNode; xpathNode = iterator.iterateNext()) {
        results.push(xpathNode);
    }
    return results;
}
export function evaluateBoolean(expression, rootNode) {
    let result;
    try {
        result = evaluateXpath(expression, rootNode, xpath.result.BOOLEAN_TYPE);
    }
    catch (_err) {
        return false;
    }
    return result.booleanValue;
}
export function evaluateString(expression, rootNode) {
    let result;
    try {
        result = evaluateXpath(expression, rootNode, xpath.result.STRING_TYPE);
    }
    catch (_err) {
        return '';
    }
    return result.stringValue;
}
export function updateEvaluator(node) {
    if (Engine.getInstance().mode !== EngineConst.Mode.HTTP)
        return;
    let parent = node;
    while (parent && !parent.evaluate) {
        parent = parent.parentNode;
    }
    if (parent && parent.evaluate) {
        xpath.currentDocument = parent;
    }
    else if (node.ownerDocument) {
        xpath.currentDocument = node.ownerDocument;
    }
}
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