rtfeldman/seamless-immutable

Incorrectly identifying promises

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#208 建立於 2017年3月18日

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 (6 留言) (0 反應) (0 負責人)JavaScript (5,367 star) (221 fork)batch import
bughelp wanted

描述

I've encountered an issue in the latest (7.1.0) release relating to commit 492d53e705acb6c

The issue is that isPromise makes a huge assumption that any object with a then method is a Promise. If the object is not a Promise, then will be called which may not be desirable.

This can be demonstrated very simply

Immutable({then:function() { console.log("should not be called") }});

I encountered this when using superagent which provides a thenable interface but is not technically a Promise. I suspect there may well be other libraries with a similar approach.

貢獻者指南

技術棧
javascript
領域
data
議題類型
bug
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。
2
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。
under 1 hour
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
JavaScript basicsPromise/A+ thenable concept
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。
70
研究方向
Examine the `isPromise` function in the codebase, likely in a utility file. The issue references commit 492d53e705acb6c where the assumption was introduced. Review the comments for suggested fixes, such as checking that `then` is a function before calling it. Consider using `Promise.resolve(value)` to detect thenables more safely, but be aware of side effects.