shared_checkers.dart

// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:analyzer/dart/element/type.dart';
import 'package:source_gen/source_gen.dart' show TypeChecker;
import 'package:source_helper/source_helper.dart';

/// A [TypeChecker] for [Iterable].
const coreIterableTypeChecker = TypeChecker.fromUrl('dart:core#Iterable');

const coreStringTypeChecker = TypeChecker.fromUrl('dart:core#String');

const coreMapTypeChecker = TypeChecker.fromUrl('dart:core#Map');

/// Returns the generic type of the [Iterable] represented by [type].
///
/// If [type] does not extend [Iterable], an error is thrown.
DartType coreIterableGenericType(DartType type) =>
    type.typeArgumentsOf(coreIterableTypeChecker)!.single;

/// Returns the generic key type of the [Map] represented by [type].
///
/// If [type] does not extend [Map], an error is thrown.
DartType coreMapGenericKeyType(DartType type) =>
    type.typeArgumentsOf(coreMapTypeChecker)![0];

/// Returns the generic value type of the [Map] represented by [type].
///
/// If [type] does not extend [Map], an error is thrown.
DartType coreMapGenericValueType(DartType type) =>
    type.typeArgumentsOf(coreMapTypeChecker)![1];

/// A [TypeChecker] for [String], [bool] and [num].
const simpleJsonTypeChecker = TypeChecker.any([
  coreStringTypeChecker,
  TypeChecker.fromUrl('dart:core#bool'),
  TypeChecker.fromUrl('dart:core#num')
]);