Derive Macro FromJSObj 

#[derive(FromJSObj)]
{
    // Attributes available to this derive:
    #[rename]
    #[js_default]
}

Derive macro for implementing deserialization from JavaScript values to Rust structs.

This macro automatically implements the FromJSObj trait for a struct, allowing it to be deserialized from JavaScript objects. Fields can be renamed using the rename attribute to match different JavaScript property names.

Attributes

• rename = "name": Use a different name for the field in JavaScript
• js_default: Use Default::default() if the field is missing
• js_default = "value": Use a specific default value if the field is missing

Field Types

• Required fields: Must exist in the JavaScript object, will error if missing
• Optional fields: Use Option<T> type, will be None if missing
• Fields with defaults: Use #[js_default] or #[js_default = "value"], will use default if missing
• All field types must implement FromJSValue

Example

#[derive(FromJSObj)]
struct Person {
    #[rename = "firstName"]
    first_name: String,
    #[rename = "lastName"]
    last_name: String,
    age: i32,
    // Optional field - will be None if missing
    nickname: Option<String>,
    // Field with default value
    #[js_default = "active"]
    status: String,
    // Field using Default::default()
    #[js_default]
    score: i32,
}

JavaScript Usage

// This will successfully deserialize
const complete = {
    firstName: "John",
    lastName: "Doe",
    age: 30,
    nickname: "Johnny",
    status: "premium"
};
// Result: Person { first_name: "John", last_name: "Doe", age: 30,
//                  nickname: Some("Johnny"), status: "premium", score: 0 }

// This will also work (using defaults)
const minimal = {
    firstName: "Jane",
    lastName: "Smith",
    age: 25
};
// Result: Person { first_name: "Jane", last_name: "Smith", age: 25,
//                  nickname: None, status: "active", score: 0 }

// This will fail with clear error message
const incomplete = {
    firstName: "John",
    lastName: "Doe"
    // Missing required field 'age'
};
// Error: "Required field 'age' is missing"

Error Handling

The macro provides detailed error messages:

• Missing required fields: “Required field ‘field_name’ is missing”
• Type conversion errors: “Failed to convert field ‘field_name’: [original error]”