目录

null_closures

目录

Do not pass null as an argument where a closure is expected.

此规则自 Dart 2.0 版本起可用。

_规则集：recommended , flutter _

此规则提供 快速修复 。

详情

#

DON'T pass null as an argument where a closure is expected.

Often a closure that is passed to a method will only be called conditionally, so that tests and "happy path" production calls do not reveal that null will result in an exception being thrown.

This rule only catches null literals being passed where closures are expected in the following locations:

Constructors

#
  • From dart:async
    • Future at the 0th positional parameter
    • Future.microtask at the 0th positional parameter
    • Future.sync at the 0th positional parameter
    • Timer at the 0th positional parameter
    • Timer.periodic at the 1st positional parameter
  • From dart:core
    • List.generate at the 1st positional parameter

Static functions

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  • From dart:async
    • scheduleMicrotask at the 0th positional parameter
    • Future.doWhile at the 0th positional parameter
    • Future.forEach at the 0th positional parameter
    • Future.wait at the named parameter cleanup
    • Timer.run at the 0th positional parameter

Instance methods

#
  • From dart:async
    • Future.then at the 0th positional parameter
    • Future.complete at the 0th positional parameter
  • From dart:collection
    • Queue.removeWhere at the 0th positional parameter
    • `Queue.retain
    • Iterable.firstWhere at the 0th positional parameter, and the named parameter orElse
    • Iterable.forEach at the 0th positional parameter
    • Iterable.fold at the 1st positional parameter
    • Iterable.lastWhere at the 0th positional parameter, and the named parameter orElse
    • Iterable.map at the 0th positional parameter
    • Iterable.reduce at the 0th positional parameter
    • Iterable.singleWhere at the 0th positional parameter, and the named parameter orElse
    • Iterable.skipWhile at the 0th positional parameter
    • Iterable.takeWhile at the 0th positional parameter
    • Iterable.where at the 0th positional parameter
    • List.removeWhere at the 0th positional parameter
    • List.retainWhere at the 0th positional parameter
    • String.replaceAllMapped at the 1st positional parameter
    • String.replaceFirstMapped at the 1st positional parameter
    • String.splitMapJoin at the named parameters onMatch and onNonMatch

BAD:

dart
[1, 3, 5].firstWhere((e) => e.isOdd, orElse: null);

GOOD:

dart
[1, 3, 5].firstWhere((e) => e.isOdd, orElse: () => null);

使用方法

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要启用 null_closures 规则，请在你的 analysis_options.yaml 文件中，在 linter > rules 下添加 null_closures ：

analysis_options.yaml
yaml
linter:
  rules:
    - null_closures

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