Top 5 Common JSON Syntax Errors and How to Fix Them
Identify and resolve the five most frequent JSON parse errors: trailing commas, unquoted keys, single quotes, and unescaped characters.
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Almost every developer has encountered the dreaded `SyntaxError: Unexpected token in JSON at position X`. Here are the top 5 culprits and how to correct them.
1. Trailing Commas
Problem: Leaving a comma after the final property in an object or array: `{"name": "Alice", "role": "admin",}` Fix: Delete the trailing comma before the closing brace or bracket.
2. Single Quotes Instead of Double Quotes
Problem: Using single quotes around strings or keys: `{'status': 'success'}` Fix: Replace all outer single quotes with double quotes: `{"status": "success"}`.
3. Unquoted Object Keys
Problem: Writing JavaScript literal shorthand: `{ userId: 101, active: true }` Fix: Wrap all key identifiers in double quotes: `{"userId": 101, "active": true}`.
4. Raw Unescaped Newlines
Problem: Multi-line strings with literal line breaks. Fix: Replace literal newlines with `\n`.
5. Leading Zeroes on Numbers
Problem: Numbers like `05` or `0123` are illegal in JSON. Fix: Remove leading zeroes: `5` or `123`.
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