ngraph.merge

const merge = require('ngraph.merge'); const defaults = { name: 'Guest', age: 30, isActive: true, settings: { theme: 'dark' } }; const userOptions = { name: 'Alice', // Same type as default, will not overwrite age: 'thirty', // Different type (string vs number), will overwrite isAdmin: false, settings: { debug: true } // New property for settings, will overwrite entire settings object if it's not a deep merge }; const finalOptions = {}; merge(finalOptions, defaults); console.log('1. After merging with defaults:', finalOptions); // Expected: { name: 'Guest', age: 30, isActive: true, settings: { theme: 'dark' } } merge(finalOptions, userOptions); console.log('2. After merging with user options:', finalOptions); // Expected: { name: 'Guest', age: 'thirty', isActive: true, isAdmin: false, settings: { theme: 'dark' } } // Note: `name` remains 'Guest' because types match. `age` becomes 'thirty' due to type mismatch. // `settings` in `userOptions` will not overwrite because the `settings` property in `finalOptions` already exists and has the same object type. console.log('Final Name:', finalOptions.name); // Expected: 'Guest' console.log('Final Age:', finalOptions.age); // Expected: 'thirty' console.log('Final Is Admin:', finalOptions.isAdmin); // Expected: false console.log('Final Settings:', finalOptions.settings); // Expected: { theme: 'dark' } - not affected by userOptions.settings because it's a shallow merge and type match.