为什么在使用babel-loader时,Object.assign()需要一个polyfill? [英] Why does Object.assign() require a polyfill when babel-loader is being used?
问题描述
我试图在由Babel编译的ESP Web应用程序中使用webpack使用 Object.assign()
,但是我收到错误:
I'm attempting to use Object.assign()
in an ES6 web app compiled by Babel with webpack, but I'm getting an error:
Uncaught TypeError: Object.assign is not a function
我已经在使用 babel-loader
将ES6转移到ES5,所以我所有的其他ES6代码正在工作。然而,在我的代码库中, Object.assign()
仅在我还导入babel-core / polyfill
之后才起作用。我看到我也可以通过导入babel-运行时间,但我想了解为什么 Object.assign()
需要多于 babel -loader
执行 - 不应该 babel-loader
预处理所有内容,包括 Object.assign()
?
I'm already using babel-loader
to transpile ES6 to ES5, so all my other ES6 code is working. Yet, Object.assign()
only works after I also import "babel-core/polyfill"
in my codebase. I see that I can also fix this by importing babel-runtime, but I'd like to understand why Object.assign()
requires more than what babel-loader
performs — shouldn't babel-loader
preprocess everything, including Object.assign()
?
推荐答案
Babel通过 babel-loader
在ES6语法中。 Babel自己绝对没有添加ES6标准库功能(如 Object.assign
)。加载聚合物填充单独的聚合物填充 core-js
,但是您可以加载所需的任何polyfill。
Babel, via babel-loader
, transpiles differences in ES6 syntax. Babel on its own does absolutely nothing to add in ES6 standard library functionality (like Object.assign
). Loading the polyfill loads a separate polyfill core-js
for you, but you can load any polyfill you want.
即使某些语法转换依赖于特定的polyfill功能来加载,因为一些语法依赖于算法以及在库代码中实现的行为。每个列表的 http://babeljs.io/docs/learn-es2015/ 上的ES6功能假定加载了什么标准库功能。
Even some syntax conversions rely on specific polyfill functionality to be loads, since some syntax relies on algorithms and behaviors implemented in library code. The ES6 features on http://babeljs.io/docs/learn-es2015/ each list what standard library functionality are assumed to have been loaded.
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