环境变量TypeScript [英] Environment Variables TypeScript

问题描述

假设我有一段代码，我只想在暂存环境中出现（或运行）。我在该环境中设置了一个环境变量（例如，ENV ='staging'），TypeScript有没有办法在编译期间访问该变量？

let's say I have a block of code that I'd like to only be present (or run) in a staging environment. I've set an environment variable in that enivronment (say, ENV = 'staging'), is there a way for TypeScript to access that variable during compilation?

示例：

if（Enivronment ['ENV'] =='staging'）console.log（'testing'）;

这将编译为（冗余但有效） if（'staging'=='staging'）... 关于上述环境？

which would compile to (the redundant, but efffective) if ('staging' == 'staging') ... on the above environment?

推荐答案

不，这是不可能的。

如果你的TypeScript文件在Node中运行，您可以使用 process.env 因为它是一个常规的Node API - 但是在这种情况下，环境变量在运行时由您编译的文件访问，而不是在TypeScript的编译时访问。

If your TypeScript file runs in Node, you can use process.env since it's a regular Node API - but in that case, the environment variable is accessed at runtime, by your compiled file, not at compile time by TypeScript.

如果您的TypeScript文件在浏览器中运行，则没有 process.env ，因此您甚至无法在运行时访问它。你可以使用像Webpack这样的工具来替换对的引用process.env 编译文件中的变量及其在构建时的相应值 - 但仍然不是TypeScript正在做的。

If your TypeScript file runs in the browser, then there is no process.env, so you cannot even access it at runtime. You could use a tool like Webpack to replace references to process.env variables in the compiled file with their respective values at build time - but that still is not TypeScript's doing.

所以不幸的是答案是否：TypeScript不能这样做，你必须使用其他东西（比如Webpack，甚至只是搜索和替换）将环境变量注入你的脚本。

So unfortunately the answer is no: TypeScript cannot do this, and you'll have to use something else (like Webpack, or even just a search and replace) to inject environment variables into your script.

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