Microsoft/TypeScript

Improve errors for potential arrow functions

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#25,898 建立於 2018年7月24日

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 (1 留言) (0 反應) (0 負責人)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.

貢獻者指南

技術棧
typescript
領域
toolingdeveloper experience
議題類型
feature
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-3 hours
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
TypeScript parser internalserror message generation
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
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.