PartBuilder class Null safety

A Builder which generates part of files.

This builder should be avoided - prefer using SharedPartBuilder and generating content that can be merged with output from other builders into a common .g.dart part file.

Each output should correspond to a part directive in the primary input, this will be validated.

Content output by each generator is concatenated and written to the output. A part of directive will automatically be included in the output and should not need be written by any of the generators.

Available Extensions


PartBuilder(List<Generator> generators, String generatedExtension, {String formatOutput(String code)?, List<String> additionalOutputExtensions = const [], String? header, bool allowSyntaxErrors = false, BuilderOptions? options})
Wrap generators as a Builder that generates part of files.


allowSyntaxErrors bool
Whether to allow syntax errors in input libraries.
final, inherited
buildExtensions Map<String, List<String>>
Mapping from input file extension to output file extensions.
final, inherited
formatOutput String Function(String)
Function that determines how the generated code is formatted.
final, inherited
hashCode int
The hash code for this object.
read-only, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited


build(BuildStep buildStep) Future
Generates the outputs for a given BuildStep.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toString() String
A string representation of this object.


operator ==(Object other) bool
The equality operator.