Xml Parser

XML Module presents a simple way to parse data from an XML content. One scenario, where similar functionality could be used is the cases when a service returns an XML response. The module allows you to go through the XML code and to search for specific attribute and its value or to take the data(e.g. text value) locked between the XML elements.

const xmlModule = require("tns-core-modules/xml");

import * as xmlModule from "tns-core-modules/xml";

Basics

The example demonstrates how to create parser event, which is needed for separating the XML into different types and for reading the saved data.

Declaring ParserEvent callback method.

const onEventCallback = (event) => {
    switch (event.eventType) {
        case xmlModule.ParserEventType.StartElement:
            if (event.attributes) {
                for (const attributeName in event.attributes) {
                    if (event.attributes.hasOwnProperty(attributeName)) {
                        source.push({
                            eventType:event.eventType,
                            elementName:event.elementName,
                            attributeName: attributeName,
                            result:event.attributes[attributeName],
                            significantText: null
                        });
                    }
                }
            } else {
                source.push({
                    eventType:event.eventType,
                    elementName:event.elementName,
                    attributeName:null,
                    result:null,
                    significantText:null
                });
            }
            break;
        case xmlModule.ParserEventType.EndElement:
            source.push({
                eventType:event.eventType,
                elementName:event.elementName,
                attributeName:null,
                result:null,
                significantText:null
            });
            break;

        case xmlModule.ParserEventType.Text:
            const significantText = event.data.trim();

            if (significantText !== "") {
                source.push({
                    eventType:event.eventType,
                    elementName:null,
                    attributeName: null,
                    result:null,
                    significantText:significantText
                });
            }
            break;
        default:
            break;
    }
};

const onErrorCallback = (error) => {
    console.log(`Error: ${error.message}`);
};

const onEventCallback = (event) => {
    switch (event.eventType) {
        case xmlModule.ParserEventType.StartElement:
            if (event.attributes) {
                for (const attributeName in event.attributes) {
                    if (event.attributes.hasOwnProperty(attributeName)) {
                        source.push({
                            eventType: event.eventType,
                            elementName: event.elementName,
                            attributeName: attributeName,
                            result: event.attributes[attributeName],
                            significantText: null
                        });
                    }
                }
            } else {
                source.push({
                    eventType: event.eventType,
                    elementName: event.elementName,
                    attributeName: null,
                    result: null,
                    significantText: null
                });
            }
            break;
        case xmlModule.ParserEventType.EndElement:
            source.push({
                eventType: event.eventType,
                elementName: event.elementName,
                attributeName: null,
                result: null,
                significantText: null
            });
            break;

        case xmlModule.ParserEventType.Text:
            const significantText = event.data.trim();

            if (significantText !== "") {
                source.push({
                    eventType: event.eventType,
                    elementName: null,
                    attributeName: null,
                    result: null,
                    significantText: significantText
                });
            }
            break;
        default:
            break;
    }
};

const onErrorCallback = (error) => {
    console.log(`Error: ${error.message}`);
};

Calling parse method.

const xmlParser = new xmlModule.XmlParser(onEventCallback, onErrorCallback);
    xmlParser.parse(`
    <Document>
        <First attr1=\ "attribute1\" attr2=\ "attribute2\">I am first</First>
        <Second>I am second</Second>
        <Third>
            <FirstChild attr3=\ "attribute3\"></FirstChild>
        </Third>
    </Document>
    `);

const xmlParser = new xmlModule.XmlParser(onEventCallback, onErrorCallback);
    xmlParser.parse(`
    <Document>
        <First attr1=\ "attribute1\" attr2=\ "attribute2\">I am first</First>
        <Second>I am second</Second>
        <Third>
            <FirstChild attr3=\ "attribute3\"></FirstChild>
        </Third>
    </Document>
    `);

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Demo Source

API Reference for the XML Class