Encoders and decoders for converting between different data representations, including JSON and UTF-8.

In addition to converters for common data representations, this library provides support for implementing converters in a way which makes them easy to chain and to use with streams.

To use this library in your code:

import 'dart:convert';

Two commonly used converters are the top-level instances of JsonCodec and Utf8Codec, named JSON and UTF8, respectively.

JSON is a simple text format for representing structured objects and collections. The JSON encoder/decoder transforms between strings and object structures, such as lists and maps, using the JSON format.

UTF-8 is a common variable-width encoding that can represent every character in the Unicode character set. The UTF-8 encoder/decoder transforms between Strings and bytes.

Converters are often used with streams to transform the data that comes through the stream as it becomes available. The following code uses two converters. The first is a UTF-8 decoder, which converts the data from bytes to UTF-8 as it's read from a file, The second is an instance of LineSplitter, which splits the data on newline boundaries.

int lineNumber = 1;
Stream<List<int>> stream = new File('quotes.txt').openRead();

stream.transform(UTF8.decoder)
      .transform(const LineSplitter())
      .listen((line) {
        if (showLineNumbers) {
          stdout.write('${lineNumber++} ');
        }
        stdout.writeln(line);
      });

See the documentation for the Codec and Converter classes for information about creating your own converters.

Constants

ASCII → AsciiCodec

An instance of the default implementation of the AsciiCodec.

const AsciiCodec()
BASE64 → Base64Codec

A base64 encoder and decoder.

const Base64Codec()
BASE64URL → Base64Codec

A base64url encoder and decoder.

const Base64Codec.urlSafe()
HTML_ESCAPE → HtmlEscape

A String converter that converts characters to HTML entities.

const HtmlEscape()
JSON → JsonCodec

An instance of the default implementation of the JsonCodec.

const JsonCodec()
LATIN1 → Latin1Codec

An instance of the default implementation of the Latin1Codec.

const Latin1Codec()
UNICODE_BOM_CHARACTER_RUNE → int

The Unicode Byte Order Marker (BOM) character U+FEFF.

0xFEFF
UNICODE_REPLACEMENT_CHARACTER_RUNE → int

The Unicode Replacement character U+FFFD (�).

0xFFFD
UTF8 → Utf8Codec

An instance of the default implementation of the Utf8Codec.

const Utf8Codec()

Classes

AsciiCodec

An AsciiCodec allows encoding strings as ASCII bytes and decoding ASCII bytes to strings.

AsciiDecoder

AsciiEncoder

This class converts strings of only ASCII characters to bytes.

Base64Codec

A base64 encoder and decoder.

Base64Decoder

Decoder for base64 encoded data.

Base64Encoder

Base64 and base64url encoding converter.

ByteConversionSink

The ByteConversionSink provides an interface for converters to efficiently transmit byte data.

ByteConversionSinkBase

This class provides a base-class for converters that need to accept byte inputs.

ChunkedConversionSink

A ChunkedConversionSink is used to transmit data more efficiently between two converters during chunked conversions.

ChunkedConverter

This class is deprecated. Extend Converter directly.

ClosableStringSink

A ClosableStringSink extends the StringSink interface by adding a close method.

Codec

A Codec encodes and (if supported) decodes data.

Converter

A Converter converts data from one representation into another.

Encoding

Open-ended Encoding enum.

HtmlEscape

Converter which escapes characters with special meaning in HTML.

HtmlEscapeMode

HTML escape modes.

JsonCodec

A JsonCodec encodes JSON objects to strings and decodes strings to JSON objects.

JsonDecoder

This class parses JSON strings and builds the corresponding objects.

JsonEncoder

This class converts JSON objects to strings.

JsonUtf8Encoder

Encoder that encodes a single object as a UTF-8 encoded JSON string.

Latin1Codec

A LatinCodec encodes strings to ISO Latin-1 (aka ISO-8859-1) bytes and decodes Latin-1 bytes to strings.

Latin1Decoder

This class converts Latin-1 bytes (lists of unsigned 8-bit integers) to a string.

Latin1Encoder

This class converts strings of only ISO Latin-1 characters to bytes.

LineSplitter

A StreamTransformer that splits a String into individual lines.

StringConversionSink

This class provides an interface for converters to efficiently transmit String data.

StringConversionSinkBase

This class provides a base-class for converters that need to accept String inputs.

StringConversionSinkMixin

This class provides a mixin for converters that need to accept String inputs.

Utf8Codec

A Utf8Codec encodes strings to utf-8 code units (bytes) and decodes UTF-8 code units to strings.

Utf8Decoder

This class converts UTF-8 code units (lists of unsigned 8-bit integers) to a string.

Utf8Encoder

This class converts strings to their UTF-8 code units (a list of unsigned 8-bit integers).

Exceptions / Errors

JsonCyclicError

Reports that an object could not be stringified due to cyclic references.

JsonUnsupportedObjectError

Error thrown by JSON serialization if an object cannot be serialized.