Fundamental Concepts
XmlParser
The XMLParser provides the ability to parse and extract data from XML documents.
Using XmlParser
To parse an xml document, first institiate the class with the ParserEvent handler.
const xmlParser = new XmlParser(this.onEventCallback);
onEventCallback(event: ParserEvent) {
switch (event.eventType) {
case ParserEventType.StartElement:
if (event.attributes) {
for (const attributeName in event.attributes) {
if (event.attributes.hasOwnProperty(attributeName)) {
console.log({
eventType: event.eventType,
elementName: event.elementName,
attributeName: attributeName,
result: event.attributes[attributeName],
significantText: null,
});
}
}
} else {
console.log({
eventType: event.eventType,
elementName: event.elementName,
attributeName: null,
result: null,
significantText: null,
});
}
break;
case ParserEventType.EndElement:
console.log({
eventType: event.eventType,
elementName: event.elementName,
attributeName: null,
result: null,
significantText: null,
});
break;
case ParserEventType.Text:
const significantText = event.data.trim();
if (significantText !== '') {
console.log({
eventType: event.eventType,
elementName: null,
attributeName: null,
result: null,
significantText: significantText,
});
}
break;
default:
break;
}
}
Then call the parse method on the instance passing it the data to be parsed.
xmlParser.parse(`
<Document>
<First attr1=\ "attribute1\" attr2=\ "attribute2\">I am first</First>
<Second>I am second</Second>
<Third>
<FirstChild attr3=\ "attribute3\"></FirstChild>
</Third>
</Document>
`)
XmlParser API
constructor
const xmlParser = new XmlParser(onEvent: (event: ParserEvent) => void, onError?: (error: Error, position: Position) => void, processNamespaces?: boolean, angularSyntax?: boolean)
Creates a new instance of the XmlParser class.
onEvent
is the callback to execute when a parser event occurs.Optional:
onError
is the callback to execute when a parser error occurs. Theerror
parameter contains the error and theposition
represents the position of the parsing error.Optional:
processNamespaces
specifies whether namespaces should be processed.
parse()
xmlParser.parse(xmlString: string)
Parses the supplied xml string.
ParserEvent
The parser event data object has the following properties.
eventType
const eventType: ParserEventType = event.eventType
Returns the type of the parser event. See ParserEventType
position
const position: Position = event.position
Returns the position (column number and line number) in the xml string where the event was generated.
prefix
const prefix: Position = event.prefix
If namespace processing is enabled, returns the prefix of the element if the eventType is ParserEventType.StartElement
or ParserEventType.EndElement
.
namespace
If namespace processing is enabled, returns the namespace of the element if the eventType is ParserEventType.StartElement
or ParserEventType.EndElement
.
elementName
Returns the name of the element if the eventType is ParserEventType.StartElement
or ParserEventType.EndElement
.
attributes
Returns a JSON object with the attributes of an element if the eventType is ParserEventType.StartElement
.
data
Returns the relevant data if the eventType is ParserEventType.Text
, ParserEventType.CDATA
or ParserEventType.Comment
.
toString()
Returns a JSON string representation of this instance.
ParserEventType
The following are the available parser event types:
StartElement
Specifies the StartElement event type.
EndElement
Specifies the EndElement event type.
ParserEventType.Text
Specifies the Text event type.
ParserEventType.CDATA
Specifies the CDATA event type.
ParserEventType.Comment
Specifies the Comment event type.
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