Arrow
A Swift library that simplifies JSON parsing with a concise arrow operator, eliminating boilerplate code.
What is Arrow?
Arrow is a Swift library that simplifies JSON parsing by introducing a concise arrow operator (<--) to map JSON data to Swift models. It eliminates the need for verbose optional unwrapping, type casting, and nil checks, making JSON handling more elegant and less error-prone. The library is part of the freshOS iOS toolset and is designed to keep model code clean and maintainable.
iOS and macOS developers working with JSON APIs in Swift, particularly those tired of writing repetitive and error-prone manual parsing code. It's ideal for Swift developers who value clean, concise code and want to reduce boilerplate in their data layer.
Developers choose Arrow because it dramatically reduces JSON parsing boilerplate with a simple, expressive syntax. Unlike manual parsing or other libraries, it offers built-in type inference, support for nested models, and flexible date handling—all while keeping models free of parsing logic.
Overview
🏹 Parse JSON with style
Use Cases
Best For
- Parsing JSON responses from REST APIs in Swift iOS apps
- Reducing boilerplate code in Swift model serialization
- Handling complex nested JSON structures with custom objects
- Mapping JSON dates with custom formats or timestamps
- Keeping Swift model definitions clean and focused on data
- Simplifying JSON parsing in Swift projects using Swift Package Manager
Not Ideal For
- Projects heavily invested in Swift's native Codable protocol for JSON serialization
- Teams prioritizing minimal third-party dependencies to reduce vendor lock-in
- Cross-platform codebases requiring consistent JSON parsing across iOS and non-Swift targets
- Applications needing fine-grained control over parsing errors or complex validation logic
Pros & Cons
Pros
The <-- operator dramatically reduces boilerplate code by eliminating verbose optional unwrapping and type casting, as shown in the README's before-and-after comparison of JSON mapping.
Automatically infers Swift types from JSON values, minimizing manual casting and reducing potential errors in mapping logic.
Handles complex nested objects and arrays through extensions, allowing deep JSON access with dot notation (e.g., json['nested.nestedValue']) for straightforward mapping.
Offers both global and per-key date formatting, simplifying date handling from various JSON formats like ISO strings or timestamps without extra code.
Cons
The non-standard arrow operator (<--) can confuse developers unfamiliar with it, potentially harming code readability and increasing onboarding time for teams.
As of version 5.1.2, only Swift Package Manager is officially supported, with Carthage and CocoaPods deprecated, which may alienate projects using legacy dependency managers.
By abstracting away optional checks, Arrow can mask parsing failures or type mismatches, making debugging more challenging in edge cases compared to manual parsing.
Frequently Asked Questions
Related Projects
SwiftyJSONThe better way to deal with JSON data in Swift.
MantleModel framework for Cocoa and Cocoa Touch
ObjectMapperSimple JSON Object mapping written in Swift
MJExtensionA fast, convenient and nonintrusive conversion framework between JSON and model. Your model class doesn't need to extend any base class. You don't need to modify any model file.
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