bytes Binary byte library

Function

bytes(value, mode) Create immutable Bytes Value, used for binary data boundaries such as serial port, TCP, UDP, WebSocket, Modbus, etc.

Bytes does not implicitly convert strings according to UTF-8 lossy. json(bytes(...)) outputs a Base64 object tagged with type: {"type":"bytes","encoding":"base64","data":"..."}.

Syntax

Parameters

Parameters	Type	Required	Default value	Description
value	String/Array/Bytes/Object	No	Empty Bytes	Bytes source. String is encoded by UTF-8 by default; Array elements must be 0 to 255; Bytes are directly multiplexed; Object can use `hex`, `base64`, `text` or `data` fields.
mode	String	No	`text`	String Input parsing mode. Optional `text`, `utf8`, `hex`, `base64`, `base64_url`.

value Object field

When value is passed into Object, the first existing field will be read in the order of the following table: hex, base64, text, data. If none of these fields exist, empty Bytes are returned.

Field	Type	Required	Default	Description
hex	String	No	None	Hexadecimal text. Whitespace, `_`, `-`, `:`, `,` are allowed as delimiters; valid hexadecimal digits must be an even number.
base64	String	No	None	Base64 text. The encoding table can be selected with the `mode` field.
mode	String/Int	No	Standard Base64	Only used if the `base64` field is present. String supports `standard_no_pad`, `no_pad`, `url_safe`, and `url_safe_no_pad`; Int supports `1` standard without padding, `2` URL security, and `3` URL security without padding.
text	Any	No	None	Convert to UTF-8 bytes in string form.
data	String/Array/Bytes/Empty/Null/Any	No	None	Generic bytes source. Bytes are directly reused; String is UTF-8; Array elements must be 0 to 255; `empty` or `null` generates empty Bytes; other values are first converted to strings and then written to UTF-8 bytes.

Return Value

Type	Description
Bytes	Returns an immutable byte value.

Method

Method	Description
len	Returns the length in bytes.
get	Read the specified index byte.
slice	Intercept byte range.
to_array	Convert to integer array.
to_hex	Convert to hexadecimal text.
to_base64	Convert to Base64 text.
to_text	Convert text strictly to UTF-8.
append	Append data and return new Bytes.

Code Examples

Notes

A single Bytes buffer is limited by BT_BYTES_LIMIT, with a default of 16777216 bytes and a maximum of 67108864 bytes.
to_text() encounters illegal UTF-8 and returns null without lossy conversion.
Bytes is an immutable value, and append() and slice() both return new Bytes.