facebookarchive/prepack

Prepack emits code containing invalid global.TypedArray access

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#2,292 创建于 2018年7月18日

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 (0 评论) (0 反应) (0 负责人)JavaScript (14,268 star) (520 fork)batch import
bughelp wantedinterpreter

描述

TypedArray is a global not exposed to the user JavaScript runtime. Try global.TypedArray in your JavaScript environment of choice. We must emit Object.getPrototypeOf(Int8Array) or similar instead of TypedArray.

Input

var TypedArray = Object.getPrototypeOf(Int8Array);
console.log(TypedArray.from.name === "from");

Output

var TypedArray;
(function() {
  var _$0 = this;

  var _$1 = _$0.TypedArray; // <-------------------- `TypedArray` is not exposed on the global object!
  _$0.TypedArray = _$1;
  console.log(true);
}.call(this));

贡献者指南

技术栈
javascriptnodejs
领域
build system
议题类型
bug
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
Understanding of JavaScript prototypesFamiliarity with Prepack's code 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。
20
研究方向
The issue is that Prepack incorrectly emits `global.TypedArray` instead of a valid expression like `Object.getPrototypeOf(Int8Array)`. To fix, locate where Prepack serializes global object property accesses and replace the usage of `TypedArray` with a reference that works in all JavaScript environments. The relevant code is likely in the serializer or environment module of Prepack. Check the source files in the `lib/` directory for handling of built in objects. The fix should ensure that the emitted code does not assume `TypedArray` is a global.