Javascript 在 Node.js 中读取环境变量
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Read environment variables in Node.js
提问by Jayesh
Is there a way to read environment variables in Node.js code?
有没有办法在 Node.js 代码中读取环境变量？
Like for example Python's os.environ['HOME'].
例如 Python 的os.environ['HOME'].
回答by Jayesh
process.env.ENV_VARIABLE
Where ENV_VARIABLEis the name of the variable you wish to access.
ENV_VARIABLE您要访问的变量的名称在哪里。
回答by Subodh Ghulaxe
When using Node.js, you can retrieve environment variables by key from the process.envobject:
使用Node.js 时，您可以通过键从process.env对象中检索环境变量：
for example
例如
var mode = process.env.NODE_ENV;
var apiKey = process.env.apiKey; // '42348901293989849243'
Here is the answer that will explain setting environment variables in node.js
这是将解释在 node.js 中设置环境变量的答案
回答by user2574650
If you want to use a string key generated in your Node.js program, say, var v = 'HOME', you can use
process.env[v].
如果您想使用在 Node.js 程序中生成的字符串键，例如var v = 'HOME'，您可以使用
process.env[v].
Otherwise, process.env.VARNAMEhas to be hardcoded in your program.
否则，process.env.VARNAME必须在您的程序中进行硬编码。
回答by Igor Litvinovich
To retrieve environment variables in Node.JS you can use process.env.VARIABLE_NAME, but don't forget that assigning a property on process.env will implicitly convert the value to a string.
要在 Node.JS 中检索环境变量，您可以使用process.env.VARIABLE_NAME，但不要忘记在 process.env 上分配属性会将值隐式转换为字符串。
Avoid Boolean Logic
避免布尔逻辑
Even if your .env file defines a variable like SHOULD_SEND=falseor SHOULD_SEND=0, the values will be converted to strings(“false” and “0”respectively) and not interpreted as booleans.
即使您的 .env 文件定义了SHOULD_SEND=false或SHOULD_SEND=0 之类的变量，这些值也将转换为字符串（分别为“false”和“0”）而不是解释为布尔值。
if (process.env.SHOULD_SEND) {
mailer.send();
} else {
console.log("this won't be reached with values like false and 0");
}
Instead, you should make explicit checks. I've found depending on the environment name goes a long way.
相反，您应该进行明确的检查。我发现根据环境名称有很长的路要走。
db.connect({
debug: process.env.NODE_ENV === 'development'
});
回答by Huy Vo
You can use envpackage to manage your environment variables per project:
您可以使用env包来管理每个项目的环境变量：
- Create a
.envfile under the project directory and put all of your variables there. - Add this line in the top of your application entry file:
require('dotenv').config();
.env在项目目录下创建一个文件并将所有变量放在那里。- 在应用程序入口文件的顶部添加这一行：
require('dotenv').config();
Done. Now you can access your environment variables with process.env.ENV_NAME.
完毕。现在您可以使用process.env.ENV_NAME.
回答by Brad Vanderbush
Why not use them in the Users directory in the .bash_profilefile, so you don't have to push any files with your variables to production?
为什么不在.bash_profile文件的 Users 目录中使用它们，这样您就不必将任何带有变量的文件推送到生产中？
