Microsoft/TypeScript

Improve errors for potential arrow functions

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#25,898 创建于 2018年7月24日

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 (1 评论) (0 反应) (0 负责人)TypeScript (48,455 star) (6,726 fork)batch import
BugDomain: Error MessagesEffort: ModerateHelp Wanted

描述

There are certain locations where arrow functions don't parse

var x = window.foo || () => {}

In these instances, it would be nice if users could get a better error message as to avoid issues like #25897.

Ideally this should not be an invasive change.

  • The change should be limited in scope.
  • The parser should continue erroring in those locations.
  • The change must not introduce change how existing valid code is parsed.

贡献者指南

技术栈
typescript
领域
toolingdeveloper experience
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
TypeScript parser internalserror message generation
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
40
研究方向
Investigate the parser's error handling in locations where arrow functions are not allowed (e.g., after ||). Look at the current error messages for syntax errors in those contexts and determine how to provide more specific hints about possible arrow function use. Check issue #25897 for related context. Ensure changes are minimal and do not affect valid code parsing.
Improve errors for potential arrow functions · Microsoft/TypeScript#25898 | Good First Issue