Deserialization

Basic Usage

Every Serde(format, T) instance exposes a deserialize method:

const json = serde.Serde(.json, MyStruct);

var result = try json.deserialize(allocator, input_bytes);
defer result.deinit();

// result.value is of type MyStruct

The returned Parsed(T) owns an arena allocator. All strings and slices in the deserialized value point into this arena. Call deinit() to free everything at once.

Error Handling

Deserialization can fail with:

error.MissingField — a required field is absent from the input
error.DuplicateField — the same key appears twice (JSON)
error.UnexpectedToken — malformed input
error.Overflow — numeric value out of range
Format-specific parse errors

Default Values

Fields with default values are optional in the input:

const Config = struct {
    host: []const u8 = "localhost",
    port: u16 = 8080,
    debug: bool = false,
};

// Input: {"port":9090}
// Result: host="localhost", port=9090, debug=false

Optional Fields

Optional fields default to null when absent:

const User = struct {
    name: []const u8,
    bio: ?[]const u8 = null,
};

// Input: {"name":"alice"}
// Result: name="alice", bio=null

Unknown Keys

Unknown keys in the input are silently ignored. This allows forward-compatible deserialization — new fields added to the struct won’t break parsing of old input.

Nested Types

Nested structs, arrays, and slices are deserialized recursively, following the same rules at each level.

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