canonicalString function

String canonicalString(Object? value)

Builds a deterministic canonical string for value.

Maps emit their keys sorted by toString(); lists keep their order; strings are quoted; null, num, and bool are normalized to plain text. Recurses to the value's nesting depth, so it is not intended for untrusted, arbitrarily-deep input (deep nesting can exhaust the stack).

Example:

canonicalString(<String, Object?>{'b': 1, 'a': 2}); // {"a":2,"b":1}

Audited: 2026-06-12 11:26 EDT

Implementation

String canonicalString(Object? value) {
  if (value == null) {
    return 'null';
  }
  // Quote strings so they can never be confused with literals like null/true.
  if (value is String) {
    return '"$value"';
  }
  if (value is bool || value is num) {
    return value.toString();
  }
  if (value is List<Object?>) {
    return _canonicalList(value);
  }
  if (value is Map<Object?, Object?>) {
    return _canonicalMap(value);
  }
  // Fallback for any other type: its own string form, quoted for safety.
  return '"$value"';
}