JS module that can be used to compress (zlib) , encode (base45) and generate QR out of given any data. Also can be used to do the operation vice versa
npm install @mosip/pixelpassPixelpass is a library which can do multiple things which are listed below,
- Given a data → generateQRCode → returns a QR Code.
- Given a JSON String → generateQRData → Gives back CBOR encoded data.
- Given a CBOR encoded data as byte array → decode → Gives back JSON String.
- Given data as byteArray → decodeBinary → Gives back JSON String.
- Given a JSON and Mapper → getMappedData → Gives back CBOR encoded data.
- Given a CBOR encoded data and Mapper → decodeMappedData → Gives back a JSON.
- Compresses the data using zlib compression of level 9.
- Encodes/ Decodes the data using base45.
- When the Data is JSON, it does the CBOR encode/decode to reduce size further.
- When JSON and a Mapper is given, it maps the JSON with Mapper and then does the CBOR encode/decode which further reduces the size of the data.
npm i @mosip/pixelpassTo run the example app copy the below command and paste it to your terminal.
``
git clone https://github.com/mosip/pixelpass.git && cd pixelpass && git checkout develop && cd js && npm i && cd example && npm i && npm start
- data - Data needs to be compressed and encoded.
- ecc - Error Correction Level for the QR generated. defaults to "L".
- header - Data header need to be prepend to identify the encoded data. defaults to "".
`javascript
import { generateQRCode } from '@mosip/pixelpass';
const data = "Hello";
const qrCode = generateQRCode(data, ecc, header);
// ecc is Error Correction Level for the QR generated. defaults to "L".
// header defaults to empty string if not passed.
`
The takes a data, ECC (Error correction level) which when not passed defaults to L and header which defaults to empty string if not passed.
Returns a base64 encoded PNG image.
- data - Data needs to be compressed and encoded.
- header - Data header need to be prepend to identify the encoded data. defaults to "".
`javascript
import { generateQRData } from '@mosip/pixelpass';
const jsonString = "{\"name\":\"Steve\",\"id\":\"1\",\"l_name\":\"jobs\"}";
const header = "jsonstring";
const encodedCBORData = generateQRData(jsonString, header);
// header defaults to empty string if not passed.
`
The takes a valid JSON string and a header which when not passed defaults to an empty string.Compressed > CBOR Encoded > Base45 Encoded
This API will return a base45 encoded string which is .
- data - Data needs to be decoded and decompressed without header.
`javascript
import { decode } from '@mosip/pixelpass';
const b45EncodedData = "NCFWTL$PPB$PN$AWGAE%5UW5A%ADFAHR9 IE:GG6ZJJCL2.AJKAMHA100+8S.1";
const jsonString = decode(b45EncodedData);
`
The will take a string as parameter and gives us decoded JSON string which is Base45 Decoded > CBOR Decoded > Decompressed.
- data - Data needs to be decoded and decompressed without header.
`javascript
import { decodeBinary } from '@mosip/pixelpass';
const zipdata =
const decompressedData = decodeBinary(zipdata);
`
The will take a UInt8ByteArray as parameter and gives us unzipped string. Currently only zip binary data is only supported.
- jsonData - A JSON data.mapper
- - A Map which is used to map with the JSON.cborEnable
- - A Boolean which is used to enable or disable CBOR encoding on mapped data. Defaults to false if not provided.
`javascript
import { getMappedData } from '@mosip/pixelpass';
const jsonData = {"name": "Jhon", "id": "207", "l_name": "Honay"};
const mapper = {"id": "1", "name": "2", "l_name": "3"};
const byteBuffer = getMappedData(jsonData, mapper,true);
const cborEncodedString = byteBuffer.toString('hex');
`
The takes 3 arguments a JSON and a map with which we will be creating a new map with keys and values mapped based on the mapper. The third parameter is an optional value to enable or disable CBOR encoding on the mapped data. { "1": "207", "2": "Jhon", "3": "Honay"}
The example of a converted map would look like,
- data - A CBOREncoded string or a mapped JSON.mapper
- - A Map which is used to map with the JSON.
`javascript
import { decodeMappedData } from '@mosip/pixelpass';
const cborEncodedString = "a302644a686f6e01633230370365486f6e6179";
const mapper = {"1": "id", "2": "name", "3": "l_name"};
const jsonData = decodeMappedData(cborEncodedString, mapper);
`
The decodeMappedData takes 2 arguments a string which is CBOR Encoded or a mapped JSON and a map with which we will be creating a JSON by mapping the keys and values. If the data provided is CBOR encoded string the API will do a CBOR decode first ad then proceed with re-mapping the data.{"name": "Jhon", "id": "207", "l_name": "Honay"}
The example of the returned JSON would look like,
- thrown when the string passed to encode is null.-
Cannot read properties of undefined (reading 'length') - thrown when the string passed to encode is undefined.-
byteArrayArg is null or undefined. - thrown when the string passed to encode is null or undefined.-
utf8StringArg is null or undefined. - thrown when the string passed to decode is null or undefined.-
utf8StringArg has incorrect length. - thrown when the string passed to decode is of invalid length.-
Invalid character at position X. - thrown when the string passed to decode is invalid with an unknown character then base45 character set. Also denotes the invalid character position.-
incorrect data check` - thrown when the string passed to decode is invalid.