Best Practices for JSON Formatter Error Recovery

Actionable Steps:

• Read the Message Carefully: Understand what the formatter *thinks* the error is. Messages like "Unexpected token," "Expected comma or closing bracket," or "Unexpected end of input" provide strong clues.
• Note the Line/Column Number: Most formatters indicate the location of the error. While the actual issue might be *before* the reported location (e.g., a missing comma on the previous line causes the *next* token to be unexpected), it narrows down the search.
• Observe Highlighting: Red highlighting points directly to the character or sequence of characters causing the problem. Pay close attention to it.

Missing/Mismatched Brackets/Braces:

Ensure every { has a matching } and every [ has a matching ]. Many editors offer bracket matching functionality.

{
  "data": [
    { "id": 1, "value": "A" }, // Missing '}' after this object
    { "id": 2, "value": "B" }
  ]
// Missing ']' for the array
// Missing '}' for the root object

Missing/Extra Commas:

Elements in an object ("key": "value" pairs) and items in an array must be separated by a comma. The *last* element/item in an object or array should *not* have a trailing comma.

{
  "name": "Example",
  "version": "1.0.0" // Missing comma here
  "settings": {
    "enabled": true,
    "limit": 100, // Trailing comma here
  }
}

Incorrect Quotes:

JSON requires double quotes " around keys and string values. Single quotes ' are not valid.

{
  'type': "config", // Single quotes around key
  "value": 'some text' // Single quotes around value
}

Malformed Values:

Numbers should follow standard numeric format. Booleans must be true or false (lowercase). Null must be null (lowercase).

{
  "count": 010, // Leading zero
  "isValid": TRUE, // Uppercase boolean
  "data": Null // Uppercase null
}

The Process:

1. Identify the first reported error by the formatter.
2. Analyze the potential cause around that location, considering the previous lines.
3. Apply the fix (e.g., add a comma, fix quotes, add a brace).
4. Re-validate or re-format the JSON.
5. The formatter should now show fewer errors, or the next error in sequence. Repeat the process until no errors remain.

Isolation Technique:

• Copy the entire problematic JSON.
• Paste it into a clean formatter/editor.
• Mentally (or by copying into separate temporary files) divide the JSON into major sections (e.g., large arrays, objects).
• Gradually remove sections and re-check for errors. If the error disappears after removing a section, the problem lies within that removed part. If it persists, the problem is elsewhere.
• Once you've isolated the general area, apply the incremental fixing method within that smaller section.

Helpful Tools/Features:

• JSON Linters: These are more robust than simple formatters and provide detailed error reports and often suggest fixes.
• Syntax Highlighting: Incorrect syntax (like single quotes) often won't be highlighted correctly, offering a visual cue before the formatter even runs.
• Code Folding: Collapse sections of your JSON to focus on specific areas and verify the overall structure (e.g., ensuring the root object/array is correctly closed).
• JSON Schema Validation: If you have a defined schema, validating against it catches errors related to missing required fields, incorrect data types, or unexpected properties, in addition to syntax errors.

Initial JSON (with errors):

{
  "user": {
    "id": 123,
    "name": 'Alice', // Error 1: Single quotes
    "isActive": true, // Error 2: Trailing comma
  },
  "roles": [
    "admin" // Error 3: Missing comma
    "editor",
    "viewer", // Error 4: Trailing comma
  ] // Error 5: Missing closing brace for user object
}

Recovery Process:

1. Formatter highlights 'Alice' and points to unexpected single quotes. Fix: Change to "Alice".
2. Formatter highlights the comma after true, or the following brace. Fix: Remove the trailing comma.
3. Formatter highlights "editor" and expects a comma or bracket before it. Fix: Add a comma after "admin".
4. Formatter highlights the comma after "viewer", or the following bracket. Fix: Remove the trailing comma.
5. Formatter indicates unexpected end of input or token after the array. Counting reveals a missing closing brace for the user object. Fix: Add } after the closing brace for the user object's content, before the "roles" key.

Corrected JSON:

{
  "user": {
    "id": 123,
    "name": "Alice",
    "isActive": true
  },
  "roles": [
    "admin",
    "editor",
    "viewer"
  ]
}