Learn which node module is required/used by which

index.js

'use strict'

////////////////////////////////////////////////////////
//// written by cowCrazy
//// place in your project root folder 
//// use like so 'node index <module to search>'
////////////////////////////////////////////////////////

var fs = require("fs");

var query, requireRegEx, usedByRegEx, requiredBy = [], usedBy = [];

process.argv.forEach(function (val, idx, array) {
    if(idx === 2){
        query = val
    }
    if(idx === 3){
        throw "Can search for one module at a time"
    }
});

if(!query){
    throw "Must supply a module to search, use this form 'node index <module to search>'"
}

// search for module required as "require(module)" or "from 'module'"
requireRegEx = new RegExp(`require *\\(["']${query}["']\\)|from *["']${query}['"]`, 'i');

// search for module used as "typeof module === 'undefined'"
usedByRegEx = new RegExp(``(typeof +${query} *={2,3} *["\`']undefined['"\`])|(["\`']undefined['"\`] *={2,3} *typeof +${query})|(if *\\( *!(window\\.)?${query} *\\))``, 'i');

// main function
function searchDir(dir){
    // get all files&dirs, ignore directories with the searched library name
    var dirLs, queryIdx
    dirLs = fs.readdirSync(dir);
    queryIdx = dirLs.indexOf(query);
    if(queryIdx > -1){
        dirLs.splice(queryIdx, 1);
    }
    for (var d = 0; d < dirLs.length; d++){
        var fileName = dirLs[d];
        if(fileName.indexOf(".js") !== -1){
            if(fs.lstatSync(dir + "/" + fileName).isFile()){
                var file = fs.readFileSync(dir + "/" + fileName, "utf8");
                file = file.replace(/\n(?!\n)/g, "");
                if(file.match(requireRegEx)){
                    var moduleName = filterModuleName(dir);
                    if(requiredBy.indexOf(moduleName) === -1){
                        requiredBy.push(moduleName);
                        return;
                    }
                    return;
                }
                if(file.match(usedByRegEx)){
                    var moduleName = filterModuleName(dir);
                    if(usedBy.indexOf(moduleName) === -1){
                        usedBy.push(moduleName);
                        return;
                    }
                    return;
                }
            }
        }
        else{
            if(fs.lstatSync(dir + "/" + fileName).isDirectory()){
                searchDir(dir + "/" + fileName);
            }
        }
    }
}

// filter module name from path
function filterModuleName(path){
    path = path.slice(15);
    return path.replace(/\/.*$/, "");
}

searchDir("./node_modules");

console.log("required by:", requiredBy);
console.log("used by:", usedBy);