from_json_to_json 0.3.0

Published Aug 12, 2025

SDKdartflutter

Platformandroidioswindowslinuxmacosweb

A small set utilities to safely convert JSON to values and back

from_json_to_json

A robust Dart package for safe, predictable, and ergonomic conversion between JSON and Dart core types. Handles edge cases, nulls, and type mismatches gracefully—making your serialization and deserialization code cleaner and more reliable.

Features

Type-safe decoding: Convert dynamic JSON values to Dart types (String, int, double, bool, List<T>, Map<K,V>, DateTime, Duration) with sensible defaults.
Graceful fallback: Never crash on nulls or invalid input—get empty, zero, or null values as appropriate.
Consistent encoding: Convert Dart types back to JSON-ready primitives.
Utility checks: Quickly verify if a string is decodable as a list or map.
Pure Dart: use in server or client.

Quick Start

dependencies:
  from_json_to_json: ^0.3.0

import 'package:from_json_to_json/from_json_to_json.dart';

final list = jsonDecodeList('[1,2,3]'); // [1, 2, 3]
final map = jsonDecodeMap('{"a":1}');
final typedList = jsonDecodeListAs<int>('[1,2,3]'); // List<int> [1, 2, 3]
final typedMap = jsonDecodeMapAs<String, int>('{"a":1}'); // Map<String, int>
final dt = dateTimeFromIso8601String('2024-01-01T12:00:00Z');
final duration = jsonDecodeDurationInSeconds('1.5'); // 1.5 seconds
final n = jsonDecodeInt('42'); // 42
final b = jsonDecodeBool('true'); // true

API Overview

Type	Function	Description
bool	`jsonDecodeBool`	Convert dynamic to bool, false if invalid
bool	`jsonEncodeBool`	Identity for bool encoding
DateTime	`dateTimeFromIso8601String`	String? → DateTime?
DateTime	`dateTimeFromMillisecondsSinceEpoch`	int? → DateTime?
DateTime	`dateTimeFromYYYYMMDDHMMSSAM`	String? → DateTime? (YYYY-MM-DD H:MM:SS AM/PM)
DateTime	`dateTimeToIso8601String`	DateTime? → String?
DateTime	`dateTimeToMillisecondsSinceEpoch`	DateTime? → int?
DateTime	`dateTimeToYYYYMMDDHMMSSAM`	DateTime? → String? (YYYY-MM-DD H:MM:SS AM/PM)
double	`jsonDecodeDouble`	Convert dynamic to double, 0 if invalid
double	`jsonDecodeNullableDouble`	Convert dynamic to double, null if invalid
double	`jsonEncodeDouble`	Identity for double encoding
Duration	`jsonDecodeDurationFromISO8601`	String? → Duration (ISO 8601 format: P1Y, P6M, P2W, P30D; shorthand like "1Y", "6M", "2W", "30D" supported with approximate conversions: 1Y=365d, 1M=30d, 1W=7d, 1D=1d)
Duration	`jsonDecodeDurationInMicroseconds`	dynamic → Duration (microseconds)
Duration	`jsonDecodeDurationInMinutes`	dynamic → Duration (minutes, supports double)
Duration	`jsonDecodeDurationInSeconds`	dynamic → Duration (seconds, supports double)
Duration	`jsonEncodeDurationInMicroseconds`	Duration → int (microseconds)
Duration	`jsonEncodeDurationInMinutes`	Duration → int (minutes)
Duration	`jsonEncodeDurationInSeconds`	Duration → int (seconds)
Duration	`jsonEncodeDurationToISO8601`	Duration → String (ISO 8601 format)
int	`jsonDecodeInt`	Convert dynamic to int, 0 if invalid
int	`jsonDecodeNullableInt`	Convert dynamic to int, null if invalid
int	`jsonEncodeInt`	Identity for int encoding
List	`jsonDecodeList`	Decode JSON to list, always returns a list
List	`jsonDecodeListAs<T>`	Decode JSON to typed List, may throw on type mismatch
List	`verifyListDecodability`	Check if input is a JSON array
Map	`jsonDecodeMap`	Decode JSON to map, always returns a map
Map	`jsonDecodeMapAs<K,V>`	Decode JSON to typed Map<K,V>, may throw on type mismatch
Map	`jsonDecodeNullableMap`	Decode JSON to map, returns null if empty/invalid
Map	`jsonDecodeThrowableMap`	Decode JSON to map, throws on error
Map	`verifyMapDecodability`	Check if input is a JSON object
String	`jsonDecodeString`	Convert dynamic to string, empty if null
String	`jsonEncodeString`	Identity for string encoding

Examples

List

jsonDecodeList('[1,2,3]'); // [1, 2, 3]
jsonDecodeListAs<int>('[1,2,3]'); // List<int> [1, 2, 3]
jsonDecodeList(''); // []
jsonDecodeList('invalid'); // throws FormatException
verifyListDecodability('[1,2]'); // true

Map

jsonDecodeMap('{"a":1}'); // {a: 1}
jsonDecodeMapAs<String, int>('{"a":1}'); // Map<String, int> {a: 1}
jsonDecodeMap(''); // {}
jsonDecodeMap('invalid'); // throws FormatException
jsonDecodeNullableMap('{}'); // null
verifyMapDecodability('{}'); // true

Numbers

jsonDecodeInt('42'); // 42
jsonDecodeDouble('3.14'); // 3.14
jsonDecodeNullableInt('foo'); // null

Bool

jsonDecodeBool('true'); // true
jsonDecodeBool('0'); // false

DateTime

dateTimeFromMillisecondsSinceEpoch(1700000000000); // DateTime
dateTimeFromIso8601String('2024-01-01T12:00:00Z'); // DateTime

Duration

jsonDecodeDurationInSeconds('1.5'); // 1.5 seconds
jsonDecodeDurationInMicroseconds('1000000'); // 1 second
jsonDecodeDurationInMinutes('2.5'); // 2 min 30 sec
jsonDecodeDurationFromISO8601('P1Y'); // 365 days
jsonDecodeDurationFromISO8601('P6M'); // 180 days
jsonDecodeDurationFromISO8601('P2W'); // 14 days
jsonDecodeDurationFromISO8601('P30D'); // 30 days
jsonDecodeDurationFromISO8601('1Y'); // 365 days (shorthand)
jsonDecodeDurationFromISO8601('6M'); // 180 days (shorthand)
jsonDecodeDurationFromISO8601('2W'); // 14 days (shorthand)
jsonDecodeDurationFromISO8601('30D'); // 30 days (shorthand)
jsonEncodeDurationToISO8601(Duration(days: 365)); // "P1Y"
jsonEncodeDurationToISO8601(Duration(days: 180)); // "P6M"
jsonEncodeDurationToISO8601(Duration(days: 14)); // "P2W"
jsonEncodeDurationToISO8601(Duration(days: 30)); // "P1M"

Development

Code Coverage

To generate and view code coverage:

Generate coverage report:

make coverage

View coverage report in browser (requires lcov):

make coverage-open

Note: If you don't have lcov installed, you can install it with:

macOS: brew install lcov
Linux: sudo apt-get install lcov
Windows: Download from http://ltp.sourceforge.net/coverage/lcov.php

Changelog

See CHANGELOG.md

License

This package is licensed under the MIT License - see the LICENSE file for details.

from_json_to_json 0.3.0⧉