varstruct-match

create varstruct codec that can match multiple data types.

Each item encoded is prefixed with a type value, I suggest using a byte or a varint.

Example

var varmatch = require('varstruct-match')
var varstruct = require('varstruct')
var VarUIntProtobuf = require('varint')

//create some simple codecs
var foobar = varstruct([
  { name: 'foo', type: VarUIntProtobuf },
  { name: 'bar', type: VarUIntProtobuf }
])

//test functions - return true if the argument can be encoded with this codec.
function isFooBar (t) { return t && t.foo && t.bar }

function isInteger (n) { return typeof n === 'number' && n % 1 === 0 }

var codec = varmatch(VarUIntProtobuf, [
  { match: 1, type: foobar, test: isFooBar },
  { match: 2, type: varstruct.VarArray(VarUIntProtobuf, foobar), test: Array.isArray },
  { match: 3, type: VarUIntProtobuf, test: isInteger }
])


//encode with the first rule
codec.encode({ foo: 1, bar: 2 })
//=> <Buffer 01 01 02>

//encode with the second rule
codec.encode([{ foo: 1, bar: 2 }, { foo: 3, bar: 4 }, { foo: 5, bar: 6 }])
//=> <Buffer 02 03 01 02 03 04 05 06>

//encode with the third rule
codec.encode(7)
//=> <Buffer 03 07>

once the codec is defined, you can just pass any valid object.

API

varmatch(tagCodec, [typeCodec1, typeCodec2, ..., typeCodecN])

create an instance, specifying the codec for the matching field.

License

MIT