getHiddenSuffixCodec

Call Signature

function getHiddenSuffixCodec<TFrom, TTo>(
    codec,
    suffixedCodecs,
): FixedSizeCodec<TFrom, TTo>;

Returns a codec that encodes and decodes values with a hidden suffix.

Encoding: Appends hidden data after encoding the main value.
Decoding: Skips the hidden suffix after decoding the main value.

This is useful for any implicit metadata that should be present in binary formats but omitted from the API.

Type Parameters

Type Parameter	Description
`TFrom`	The type of the main value being encoded.
`TTo`	The type of the main value being decoded.

Parameters

Parameter	Type	Description
`codec`	`FixedSizeCodec`<`TFrom`, `TTo`>	The codec for the main value.
`suffixedCodecs`	readonly `FixedSizeCodec`<`void`>[]	A list of void codecs that produce the hidden suffix.

Returns

FixedSizeCodec<TFrom, TTo>

A FixedSizeCodec or VariableSizeCodec for encoding and decoding values with a hidden suffix.

Example

Encoding and decoding a value with suffixed constants.

const codec = getHiddenSuffixCodec(getUtf8Codec(), [
  getConstantCodec(new Uint8Array([1, 2, 3])),
  getConstantCodec(new Uint8Array([4, 5, 6])),
]);
 
const bytes = codec.encode('Hello');
// 0x48656c6c6f010203040506
//   |         |     └-- Our second hidden suffix.
//   |         └-- Our first hidden suffix.
//   └-- Our encoded value ("Hello").
 
codec.decode(bytes);
// 'Hello'

Remarks

If all you need is padding zeroes after a value, consider using padRightCodec instead.

Separate getHiddenSuffixEncoder and getHiddenSuffixDecoder functions are available.

const bytes = getHiddenSuffixEncoder(getUtf8Encoder(), [
  getConstantEncoder(new Uint8Array([1, 2, 3])),
  getConstantEncoder(new Uint8Array([4, 5, 6])),
]).encode('Hello');
 
const value = getHiddenSuffixDecoder(getUtf8Decoder(), [
  getConstantDecoder(new Uint8Array([1, 2, 3])),
  getConstantDecoder(new Uint8Array([4, 5, 6])),
]).decode(bytes);

See