[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › Bytes Bytes: `Uint8Array` helpers, the [Buffer](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/Buffer) codec, and byte sizes. Sizes follow the same pattern as durations in Time.ts: - [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength) is the canonical unit, a validated number of bytes. - [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral) is the human-readable form, such as `"10MiB"`, validated at compile time and runtime. - [ByteSize](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSize) is what APIs accept: `ByteSizeLiteral | ByteLength`. - [byteSizeToByteLength](https://evolu.dev/docs/api-reference/common/Bytes/functions/byteSizeToByteLength) normalizes a `ByteSize` to a `ByteLength`. - [ByteLengthFromString](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLengthFromString) parses either form from text. Buffer-based decoding functions throw instead of returning [Result](https://evolu.dev/docs/api-reference/common/Result/type-aliases/Result). Result is not slow, but every successful decode would allocate one, and a protocol message decodes many values. Throwing is the safe bet for that hot path until benchmarks cover the alternatives. Callers convert a thrown error into a Result once, at the boundary, as `parseProtocolHeader` in Protocol.ts does. ## Classes | Class | Description | | ----------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [BufferError](https://evolu.dev/docs/api-reference/common/Bytes/classes/BufferError) | Custom error for [Buffer](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/Buffer)-related failures like premature end of data. Provides better stack traces for debugging binary protocol issues. | ## Functions | Function | Description | | ----------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [byteSizeToByteLength](https://evolu.dev/docs/api-reference/common/Bytes/functions/byteSizeToByteLength) | Converts a [ByteSize](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSize) to a [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength). A [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength) is returned unchanged. | | [bytesToHex](https://evolu.dev/docs/api-reference/common/Bytes/functions/bytesToHex) | Convert byte array to hex string. Uses built-in function, when available. | | [bytesToUtf8](https://evolu.dev/docs/api-reference/common/Bytes/functions/bytesToUtf8) | Converts bytes to string using UTF8 encoding. | | [concatBytes](https://evolu.dev/docs/api-reference/common/Bytes/functions/concatBytes) | Copies several Uint8Arrays into one. | | [createBuffer](https://evolu.dev/docs/api-reference/common/Bytes/functions/createBuffer) | Creates a [Buffer](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/Buffer) for efficient byte operations. | | [createRunLengthEncoder](https://evolu.dev/docs/api-reference/common/Bytes/functions/createRunLengthEncoder) | Creates an incremental run-length encoder. | | [decodeFlags](https://evolu.dev/docs/api-reference/common/Bytes/functions/decodeFlags) | Decodes a byte into an array of boolean flags. | | [decodeJsonValue](https://evolu.dev/docs/api-reference/common/Bytes/functions/decodeJsonValue) | Decodes a [JsonValue](https://evolu.dev/docs/api-reference/common/Type/variables/JsonValue) using the MessagePack format. | | [decodeNonNegativeInt](https://evolu.dev/docs/api-reference/common/Bytes/functions/decodeNonNegativeInt) | Decodes a non-negative integer from a variable-length integer format. | | [decodeNumber](https://evolu.dev/docs/api-reference/common/Bytes/functions/decodeNumber) | - | | [decodeRle](https://evolu.dev/docs/api-reference/common/Bytes/functions/decodeRle) | Decodes a run-length encoded sequence. | | [decodeString](https://evolu.dev/docs/api-reference/common/Bytes/functions/decodeString) | Decodes a length-prefixed UTF-8 string. | | [encodeFlags](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeFlags) | Encodes an array of boolean flags into a single byte. | | [encodeJsonValue](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeJsonValue) | Encodes a [JsonValue](https://evolu.dev/docs/api-reference/common/Type/variables/JsonValue) using the MessagePack format. | | [encodeLength](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeLength) | Encodes the length of an array-like value. | | [encodeNonNegativeInt](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeNonNegativeInt) | Encodes a non-negative integer into a variable-length integer format. It's more efficient than encoding via [encodeNumber](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeNumber). | | [encodeNumber](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeNumber) | Evolu uses MessagePack to handle finite numbers except for NonNegativeInt. For NonNegativeInt, Evolu provides more efficient encoding. | | [encodeString](https://evolu.dev/docs/api-reference/common/Bytes/functions/encodeString) | Encodes a length-prefixed UTF-8 string. | | [hexToBytes](https://evolu.dev/docs/api-reference/common/Bytes/functions/hexToBytes) | Convert hex string to byte array. Uses built-in function, when available. | | [utf8ToBytes](https://evolu.dev/docs/api-reference/common/Bytes/functions/utf8ToBytes) | Converts string to bytes using UTF8 encoding. | ## Interfaces | Interface | Description | | ------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [Buffer](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/Buffer) | A Buffer is a dynamic, resizable container for binary data, optimized for scenarios where the final size is unknown. It grows exponentially (doubling its capacity) to minimize memory reallocations and uses `subarray` for efficient, copy-free data access in methods like `unwrap` and `shift`. | | [ByteLengthError](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/ByteLengthError) | Error returned when [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength) rejects negative zero. | | [ByteLengthFromStringError](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/ByteLengthFromStringError) | Error returned when a string is neither a number of bytes nor a [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralError](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/ByteSizeLiteralError) | Error returned when [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral) rejects a value. | | [RunLengthEncoder](https://evolu.dev/docs/api-reference/common/Bytes/interfaces/RunLengthEncoder) | Incrementally encodes consecutive equal values using run-length encoding. | ## Type Aliases | Type Alias | Description | | ---------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteLength) | Non-negative safe integer number of bytes. | | [ByteSize](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSize) | [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral) or [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength). | | [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSizeLiteral) | Byte length literal Type with compile-time and runtime validation. | | [ByteSizeLiteralBytes](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSizeLiteralBytes) | Bytes: `"0B"` to `"1023B"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralGiB](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSizeLiteralGiB) | GiB: `"1GiB"` to `"1023GiB"` or `"1.5GiB"` to `"1023.5GiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralKiB](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSizeLiteralKiB) | KiB: `"1KiB"` to `"1023KiB"` or `"1.5KiB"` to `"1023.5KiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralMiB](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSizeLiteralMiB) | MiB: `"1MiB"` to `"1023MiB"` or `"1.5MiB"` to `"1023.5MiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralTiB](https://evolu.dev/docs/api-reference/common/Bytes/type-aliases/ByteSizeLiteralTiB) | TiB: `"1TiB"` to `"1023TiB"` or `"1.5TiB"` to `"1023.5TiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | ## Variables | Variable | Description | | ------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength) | Non-negative safe integer number of bytes. | | [ByteLengthFromString](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLengthFromString) | Transforms a number of bytes or a [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral) in text into a [ByteLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteLength). | | [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral) | Byte length literal Type with compile-time and runtime validation. | | [ByteSizeLiteralBytes](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteralBytes) | Bytes: `"0B"` to `"1023B"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralGiB](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteralGiB) | GiB: `"1GiB"` to `"1023GiB"` or `"1.5GiB"` to `"1023.5GiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralKiB](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteralKiB) | KiB: `"1KiB"` to `"1023KiB"` or `"1.5KiB"` to `"1023.5KiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralMiB](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteralMiB) | MiB: `"1MiB"` to `"1023MiB"` or `"1.5MiB"` to `"1023.5MiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [ByteSizeLiteralTiB](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteralTiB) | TiB: `"1TiB"` to `"1023TiB"` or `"1.5TiB"` to `"1023.5TiB"`. See [ByteSizeLiteral](https://evolu.dev/docs/api-reference/common/Bytes/variables/ByteSizeLiteral). | | [decodeLength](https://evolu.dev/docs/api-reference/common/Bytes/variables/decodeLength) | Decodes an array-like value length. |