'use strict' module.exports = isOptional const isOptDep = require('./is-opt-dep.js') const moduleName = require('../utils/module-name.js') function isOptional (node, seen) { if (!seen) seen = new Set() // If a node is not required by anything, then we've reached // the top level package. if (seen.has(node) || node.requiredBy.length === 0) { return false } seen.add(node) const swOptional = node.fromShrinkwrap && node.package._optional const result = node.requiredBy.every(function (req) { if (req.fakeChild && swOptional) return true return isOptDep(req, moduleName(node)) || isOptional(req, seen) }) seen.delete(node) return result }