SSB BFE
Javascript implementation of the SSB binary field encodings spec.
The spec only has one type of nil, but JavaScript has two: null
and
undefined
. ssb-bfe will treat these two values in a way that mirrors what
JSON.stringify does:
- BFE Encoding an object with a
null
field becomes an object with the
nil marker
- Similar to
JSON.stringify({a: null}) === '{"a": null}'
- BFE Encoding an array with a
null
element becomes an array with the
nil marker
- Similar to
JSON.stringify([null]) === '[null]'
- BFE Encoding an object with a
undefined
field will omit that field
- Similar to
JSON.stringify({a: undefined}) === '{}'
- BFE Encoding an array with an
undefined
element becomes an array with
the nil marker
- Similar to
JSON.stringify([undefined]) === '[null]'
API
encode(input)
Takes any JavaScript primitive and returns its encoded counterpart. Is applied
recursively in case the input is an object or an array. All inputs are converted
to TFD Buffers, except for objects, arrays, and numbers, which remain the
same.
decode(input)
Takes an encoded value (such as the output from encode
) and returns the
decoded counterparts as JavaScript primitives.
decodeTypeFormat(input, typeName, formatName)
Takes an encoded value (such as the output from encode
), a typeName
and formatName and returns the decoded counterparts as JavaScript
primitives. This is much faster than decode if you know the type.
bfeTypes
Returns the bfe.json
object that can be used to look up information
based on Type and Field. Example:
const { bfeTypes } = require('ssb-bfe')
const classic_key_size = bfeTypes[0][0].data_length
bfeNamedTypes
Returns the bfe.json
object converted to a map where the keys are
the type and format names. Example:
const { bfeNamedTypes } = require('ssb-bfe')
const FEED = bfeNamedTypes['feed']
const CLASSIC_FEED_TF = Buffer.from([FEED.code, FEED.formats['classic'].code])
toTF(typeName, formatName)
Sometimes when you're wanting to check what sort of buffer you're handling, you want
to pivot on the type and format bytes.
const CLASSIC_MSG_TF = Buffer.from([1, 0])
if (buf.slice(0, 2).equals(CLASSIC_MSG_TF)) {
}
because remembering those codes is tricky, it's safer to use this convenience method:
const CLASSIC_MSG_TF = bfe.toTF('msg', 'classic')
If you remembered the type or format name wrong, you'll instantly get an error!
Check whether a buffer is an encoded type
Given any input, these functions tell you whether the input is of the specified
type (and format, if applicable). Example:
const bfe = require('ssb-bfe')
const x = bfe.encode('@6CAxOI3f+LUOVrbAl0IemqiS7ATpQvr9Mdw9LC4+Uv0=.ed25519')
bfe.isEncodedFeedClassic(x)
List of functions:
isEncodedFeed(input) => boolean
isEncodedFeedClassic(input) => boolean
isEncodedFeedGabbygroveV1(input) => boolean
isEncodedFeedBamboo(input) => boolean
isEncodedFeedBendybuttV1(input) => boolean
isEncodedFeedButtwooV1(input) => boolean
isEncodedMessage(input) => boolean
isEncodedMessageClassic(input) => boolean
isEncodedMessageGabbygroveV1(input) => boolean
isEncodedMessageCloaked(input) => boolean
isEncodedMessageBamboo(input) => boolean
isEncodedMessageBendybuttV1(input) => boolean
isEncodedMessageButtwooV1(input) => boolean
isEncodedBlob(input) => boolean
isEncodedBlobClassic(input) => boolean
isEncodedEncryptionKey(input) => boolean
isEncodedEncryptionKeyBox2DmDh(input) => boolean
isEncodedEncryptionKeyBox2PoboxDh(input) => boolean
isEncodedSignature(input) => boolean
isEncodedSignatureMsgEd25519(input) => boolean
isEncodedEncrypted(input) => boolean
isEncodedEncryptedBox1(input) => boolean
isEncodedEncryptedBox2(input) => boolean
isEncodedGeneric(input) => boolean
isEncodedGenericStringUTF8(input) => boolean
isEncodedGenericBoolean(input) => boolean
isEncodedGenericNil(input) => boolean
isEncodedGenericAnyBytes(input) => boolean
isEncodedIdentity(input) => boolean
isEncodedIdentityPoBox(input) => boolean