Master JSON validation and linting. Learn how to diagnose syntax errors, validate JSON Schema compliance, and handle invalid JSON in production APIs.
Frequently Asked Questions
Q1. What is the difference between JSON syntax validation and JSON Schema validation?
Syntax validation checks if a text string complies with JSON grammatical rules (e.g., quotes, brackets, commas). JSON Schema validation verifies whether valid JSON contains required keys, expected data types, string length limits, or numeric ranges.
Q2. Why does trailing comma cause error in JSON?
According to RFC 8259, JSON syntax does not permit trailing commas after the last property or array item. Including a trailing comma causes JSON.parse() to throw a SyntaxError: Unexpected token error.
Q3. How do I catch JSON parsing errors in JavaScript safely?
Always wrap JSON.parse() calls in a try-catch block to handle unexpected user or network payloads gracefully without crashing the application thread.
Q4. Can JSON contain comments?
Standard JSON (RFC 8259) strictly forbids comments (// or / /). If you need comments in configuration files, consider JSONC (JSON with Comments) or YAML.