Class JsonService

Fixes an invalid json like this: [ { id: 1, name: 'Alice', description: 'Lorem ipsum dolor', isActive: true, tags: ['typescript', 'javascript'], scripts: [], profile: { age: 30, location: 'Berlin' }, preferences: [{ key: 'theme', value: 'dark' }] }, { id: 2, name: 'Marc', description: 'Lorem ipsum dolor', isActive: false, tags: ['java', 'javascript'], scripts: [], profile: { age: 55, location: 'Frankfurt' }, preferences: [{ key: 'theme', value: 'light' }] }, { id: null, name: 'Bob', isActive: false, tags: null, scripts: [], profile: { age: 25, location: 'Frankfurt' }, preferences: [{ key: 'language', value: 'de' }]

into a valid json string by adding '}]'.