| // Copyright (c) 2017, 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/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| |
| import '../analyzer.dart'; |
| |
| const _desc = r'Use a function declaration to bind a function to a name.'; |
| |
| const _details = r''' |
| |
| **DO** use a function declaration to bind a function to a name. |
| |
| As Dart allows local function declarations, it is a good practice to use them in |
| the place of function literals. |
| |
| **BAD:** |
| ``` |
| void main() { |
| var localFunction = () { |
| ... |
| }; |
| } |
| ``` |
| |
| **GOOD:** |
| ``` |
| void main() { |
| localFunction() { |
| ... |
| } |
| } |
| ``` |
| |
| '''; |
| |
| class PreferFunctionDeclarationsOverVariables extends LintRule |
| implements NodeLintRule { |
| PreferFunctionDeclarationsOverVariables() |
| : super( |
| name: 'prefer_function_declarations_over_variables', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this); |
| registry.addVariableDeclaration(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitVariableDeclaration(VariableDeclaration node) { |
| if (node.initializer is FunctionExpression) { |
| final function = node.thisOrAncestorOfType<FunctionBody>(); |
| if (function == null || |
| !function.isPotentiallyMutatedInScope(node.declaredElement)) { |
| rule.reportLint(node); |
| } |
| } |
| } |
| } |