如何在 nodejs 中使用 NODE_PATH 避免 require(..\\..\\src\\test)

Question

How can I replace long relative file paths like require(..\\..\\src\\test) with the more convenient notation require(src\\test) ?

I try the solution of NODE_PATH in package.json following this article: https://www.coreycleary.me/escaping-relative-path-hell/

but when run npm start , I get a 'MODULE_NOT_FOUND' error.

My package.json look like this:

"scripts": {
    "start": "NODE_PATH=/src/zip && node index.js"
  },

I work in a windows environment and get the error 'NODE_PATH' is not recognized as an internal or external command, operable program or batch file .

Answer 1

You can manually replace the path before \\src\\test with /*$__dirname$*/ and then read the JSON file from your node application, and replace /*$__dirname$*/ with the value of the __dirname JavaScript variable.

So do this before creating the server or listening to it.

const fs = require('fs');
const jsonFilePath = '<path>';

// Read the json file
let json = fs.readFileSync(jsonFilePath, 'utf-8');

if(json.includes('/*$__dirname$*/')) {
    // Replace /*$__dirname$*/ with the variable __dirname's value
    json = json.replace('/*$__dirname$*/', __dirname);
    
    // Change the JSON file text
    fs.writeFile('jsonFilePath', json, (err) => {
        if(err) { console.log(err); }
    });
};

Answer 2

There is a solution to this without changing any process.env variables.

You can use the package.json exports field. More information about this is on the node.js docs . The exports field can be used to define exported files and directories. For example, if your package name is my-package and you want to make the /deep/deeper/src/ folder available as just my-package/src , you can use the exports field.

Example:

Files:

deep/
    deeper/
        src/
            test.js
            more.js
package.json
index.js

package.json content:

{
    "name": "my-module"
    "exports": {
        ".": "./index.js"
        "./src/": "./deep/deeper/src"
    }
}

Note: The / after ./src tells node that it's for everything in /src/ , not just a file named /src .

index.js content:

//Self referencing the module is allowed if you use --experimental-modules flag.
require("my-package/src/test");

//This is the 'hell' that you would be avoiding.
require("./deep/deeper/src/test");

I like this solution because you can specify many different paths and files just by changing package.json . The files in the module can refer their own package which this section of the docs explains.

Note: Depending on the version of node you are using, you might need to use the --exerimental-modules flag. For example:

node --experimental-modules index.js