require-chain v2.1.0

Require Chain

This package is useful when watching file changes and hot-reload modules. It helps us retrieve all the dependency or the dependent files that related to the changed file, and we can reload them all at once.

Example

import { findDependents, findDependencies } from "require-chain";
import * as path from "path";

const filename = path.join(__dirname, "test", "foo.js");

const dependents = findDependents(filename);
console.log(dependents);
// [...] filenames that rely on the given file

const dependencies = findDependencies(filename);
console.log(dependencies);
// [...] filenames that imported by the given file

API

findDependents(filename[, includes])

Finds all the CommonJS files and their ancestors that require the filename.

• filename: string | string[] The absolute path of the file (or files).
• includes: string[] | ((files: string[]) => string[]) By default, the function searches every cached file except the ones in node_modules and the require.main.filename. We can provide this argument to set more specific files that can be searched.

findDependencies(filename[, includes])

Finds all the CommonJS files and their descendants that required by the filename.

• filename: string | string[] The absolute path of the file (or files).
• includes: string[] | ((files: string[]) => string[]) By default, the function searches every cached file except the ones in node_modules and the require.main.filename. We can provide this argument to set more specific files that can be searched.

module.parent vs module.children

When a module (CommonJS file) is required, the module.parent property is assigned to the first dependent module (AKA the initiator). However, there may be many dependent files that require the same module, so reversing the module.parent to find its ancestors cannot retrieve all the dependents.

module.children, on the other hand, stores all the child modules that the current module requires, which can be used to scan for the dependency map through the require.cache and retrieve all the related files.

And of course, this package use module.children under the hood.