JSON Pointer Array Index Token Check
Audit a decoded JSON Pointer array index token: canonical decimal, safe integer, in-range and optional append marker are distinct checks.
Description
Audit a decoded JSON Pointer array index token: canonical decimal, safe integer, in-range and optional append marker are distinct checks.
A JSON Pointer token identifies an array element only when its spelling is a canonical nonnegative decimal index. An append marker is a separate application choice.
When to use this tool
Audit a decoded JSON Pointer array index token: canonical decimal, safe integer, in-range and optional append marker are distinct checks.
- Prepare the supplied token, arrayLength, allowAppend fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter token, arrayLength, allowAppend. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.canonicalIndex, result.safeIndex, result.withinArray, result.appendAllowed. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Test token against zero or a nonzero digit followed by digits, then require a JavaScript safe integer. Return its numeric index when representable, whether it is below arrayLength, and whether the exact token "-" is allowed by allowAppend.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| token | token. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| arrayLength | array length. | Integer from 0 to 1e9 inclusive |
| allowAppend | Explicit choice for allow append; supply a boolean rather than a text label. | true or false |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.canonicalIndex | Flag for canonical index under the exact condition described above. |
| result.safeIndex | Representable canonical array-index token as a number, or null when the token is not such an index. |
| result.withinArray | Flag for within array under the exact condition described above. |
| result.appendAllowed | Whether token is exactly "-" and the caller enabled append; independent of existing-element membership. |
{
"input": {
"token": "01",
"arrayLength": 3,
"allowAppend": true
},
"output": {
"result": {
"canonicalIndex": false,
"safeIndex": null,
"withinArray": false,
"appendAllowed": false
}
}
}Limitations and assumptions
- Leading zeros, signs and whitespace are not canonical indexes. The append marker does not identify an existing element. This checks one token against a supplied length, without resolving a document.
- Decoded JSON is bounded to 20,000 nodes and 32 nesting levels; record arrays have at most 128 records. Parsed number values use JavaScript floating point rather than arbitrary-precision decimal arithmetic.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
For document-wide requirements, combine these structural inventories with an explicit JSON Schema. Preserve the distinction between missing properties and null values, and between numbers and numeric-looking strings when building joins or indexes.
References
Similar or alternative tools
- JSON Pointer Parent and Final Token
Split an RFC 6901 pointer into parent pointer and decoded final token; root has no parent or final token.
- JSON Pointer Token Escaper
Escape one RFC 6901 token in the required tilde-then-slash order; not a document resolver.