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Encode/decode CBOR

Build Status NPM version

This package provides an extensible CBOR encoder/decoder.


var CBOR = require('cbor-sync');

var encodedBuffer = CBOR.encode({hello: 'world'});
var decodedObject = CBOR.decode(encodedBuffer);


Much like the toJSON() method, which allows objects to provide a replacement representation for encoding, this package checks for a toCBOR() method.

Note that this step happens after any semantic-tagging/-replacement step, so a custom semantic encoder will always override an objects built-in toCBOR() method.

Semantic extensions

CBOR provides a limited set of basic types (similar to JSON), but provides semantic tagging (optional for both encoder/decoder) that lets you annotate parts of the data so they can be decoded appropriately.

Here is an example (from this module) for encoding Date objects as ISO strings:

// 0 is the CBOR semantic tag number for date/time strings:
CBOR.addSemanticEncode(0, function (data) {
	if (data instanceof Date) {
		return data.toISOString();
CBOR.addSemanticDecode(0, function (dateString) {
	return new Date(dateString);

Known issues

  • All floats encoded as 64-bit, regardless of whether they strictly need to be