Why xtagger?

xtagger is a simple node package based on sax to get the XML structure of xml file using streams!

This package is useful in case you want to read a huge xml file in chunks. There are few npm packages like xml-flow & xml-stream which accept a repeating node to parse one xml node at a time using streams. The problem here is - how to find the appropriate repeating xml node?

xtagger helps you to find the appropriate node as it outputs the xml structure using streams.

Simply do npm i xtagger --save to install the package.

APIs

xtagger exposes 2 properties -

getXTagger(options)

This property is a function that triggers xtagger. It returns a duplex stream that can be piped with a readbale stream.

options manipulates the behavior of xml streamer. Check sax options for all the details.

xTaggerEvent: EventEmitter

xtagger fires an event after successful data processing. xTaggerEvent listens to the fired event & the event handler function provides the generated xml structure.

Example

Typescript

import { createReadStream } from "fs";
import { getXTagger, xTaggerEvent } from "xtagger";

// options for sax stream API with default values
const options: any = {
    "strict": false,
    "trim": false,
    "normalize": false,
    "lowercase": false,
    "xmlns": false,
    "noscript": false,
    "position": false
};

xTaggerEvent.once("xtagger", (response: any) => console.log(response));
createReadStream("file-path").pipe(getXTagger(options));

Javascript

const fs = require("fs");
const xtagger = require("xtagger");

// options for sax stream API with default values
const options = {
    "strict": false,
    "trim": false,
    "normalize": false,
    "lowercase": false,
    "xmlns": false,
    "noscript": false,
    "position": false
};

xtagger.xTaggerEvent.once("xtagger", (response) => console.log(response));
fs.createReadStream("file-path").pipe(xtagger.getXTagger(options));

Sample XML

<breakfast_menu>
    <food>
        <name>Belgian Waffles</name>
        <price>$5.95</price>
        <description>
            Two of our famous Belgian Waffles with plenty of real maple syrup
        </description>
        <calories>650</calories>
    </food>
    <food>
        <name>Strawberry Belgian Waffles</name>
        <price>$7.95</price>
        <description>
            Light Belgian waffles covered with strawberries and whipped cream
        </description>
        <calories>900</calories>
    </food>
</breakfast_menu>

Output

In case of above XML, the output structure would look like -

{
    "breakfast_menu": { "1": 1 },
    "food": { "2": 2 },
    "name": { "3": 2 },
    "price": { "3": 2 },
    "description": { "3": 2 },
    "calories": { "3": 2}
}

The top level keys represent the tag names. Every tage name is an object where key represents the hierarchy of the tag in xml strcture whereas value is the count of the tag name in the XML file.

The generalised structure format looks like this -

structure: { [name: string]: { [hierarchy: number]: number } };

In case of multiple occurance of the same tag name at different hierarchy levels, tag name gets following JSON structure to provide the distribution of the counts at different hierarchy levels -

{
    "breakfast_menu": { "1": 1 },
    "food": { "2": 2 },
    "name": { "3": 2 },
    "price": { "3": 2 },
    "description": { "3": 2, "4": 2 }, // description tag is present at level 3 & 4
    "calories": { "3": 2}
}

Demo

Checkout the repository. Install dependencies with command npm i & run npm start command to start the demo.

Test

Checkout the repository. Install dependencies with command npm i & run npm run test command to run the tests.

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• Author - Manoj Chalode (manojc)
• Copyright - [email protected]