LenientConverters

public enum LenientConverters

A collection of lenient converters that can handle type mismatches in JSON data.

These converters attempt multiple conversion strategies when the actual type in JSON differs from the expected type. They follow a fail-safe pattern: returning nil for invalid or non-representable values rather than crashing or producing corrupted data.

Edge cases handled:

  • Integer overflow: NaN values return nil; values outside Int.min...Int.max (including infinities) are clamped to Int.min/Int.max
  • Special float values: Double.nan is treated as invalid; Double.infinity and -Double.infinity are clamped in integer conversions
  • String parsing: Invalid formats return nil rather than crashing
  • Type mismatches: Missing or incompatible types return nil

Example usage:

let payload: DataObject = ...
let timeout = payload.getConvertible(key: "timeout", converter: LenientConverters.double)
let retryCount = payload.getConvertible(key: "retryCount", converter: LenientConverters.int)
let isEnabled = payload.getConvertible(key: "isEnabled", converter: LenientConverters.bool)

Double Converter

  • A lenient converter to Double values.

    This converter attempts the following conversions in order:

    1. Direct extraction as Double
    2. Extraction as String and parsing via DataItemFormatter (uses en_US_POSIX locale)

    Declaration

    Swift

    public static let double: any DataItemConverter<Double>

Int Converter

  • int

    A lenient converter to Int values.

    This converter attempts the following conversions in order:

    1. Direct extraction as Int (uses NSNumber’s intValue which clamps to Int.min/Int.max and truncates decimals)
    2. Extraction as String and parsing via DataItemFormatter (truncates decimal part)

    Returns nil for values that:

    • Cannot be parsed as numbers

    Note

    Out-of-bounds Double values are clamped to Int.min/Int.max (NSNumber behavior)

    Declaration

    Swift

    public static let int: any DataItemConverter<Int>

Bool Converter

  • A lenient converter to Bool values.

    This converter attempts the following conversions in order:

    1. Direct extraction as Bool
    2. Extraction as String and parsing common boolean representations:
      • “true”, “yes”, “1” → true
      • “false”, “no”, “0” → false (case-insensitive)
    3. Extraction as whole number where 0 is false and 1 is true

      Note

      Decimal numbers (e.g., 1.5) and integers other than 0 or 1 will return nil

    Returns nil for values that:

    • Any other strings non-conforming to the rule above
    • Any numbers other than 0 or 1

    Declaration

    Swift

    public static let bool: any DataItemConverter<Bool>

String Converter

  • A lenient converter to String values.

    This converter attempts the following conversions in order:

    1. Direct extraction as String
    2. Conversion of Bool to “true” or “false”
    3. Conversion of numeric types (Double, Int) to String using DataItemFormatter
      • Special values: Double.nan → "NaN", Double.infinity → "Infinity"
      • Whole numbers: 1.0 → "1" (removes unnecessary “.0” suffix)
      • Disables scientific notation for better readability

    Declaration

    Swift

    public static let string: any DataItemConverter<String>