How to change it programmatically ?

let path = require("path");
// New search path
let absolutePathToModule1 = path.resolve("./path/to/module1"); 
let absolutePathToModule2 = path.resolve("./path/to/module2"); 
let nodeSearchPaths = absolutePathToModule1+path.delimiter+absolutePathToModule2;
// Overwrite and implements
if(typeof process.env.NODE_PATH !== 'undefined'){
        process.env.NODE_PATH = process.env.NODE_PATH + path.delimiter + nodeSearchPaths ;
} else {
   process.env.NODE_PATH = nodePaths;
}
require("module").Module._initPaths();

How to change it at start in package.json ?

In package.json, you need to set it up in:

• the script node
• with the cross-env cli to support linux and windows

Example:

"scripts": {
       "dev": "cross-env NODE_PATH=./my/module/home/directory main.js",
}

How to split it / filter / map

process.env.NODE_PATH = (process.env.NODE_PATH || '')
  .split(path.delimiter)
  .filter(folder => folder && !path.isAbsolute(folder))
  .map(folder => path.resolve(appDirectory, folder))
  .join(path.delimiter);