Function struct

libraries/struct/src/struct.ts:82–248

(
    fields: Fields,
    options: {
        littleEndian: boolean;
        extra?: (Extra & ThisType<FieldsValue<Fields>>) | undefined;
        postDeserialize?:
            | ((
                  this: FieldsValue<Fields> & ExtraToIntersection<Extra>,
                  value: FieldsValue<Fields> & ExtraToIntersection<Extra>,
              ) => PostDeserialize)
            | undefined;
    },
)

/* #__NO_SIDE_EFFECTS__ */
export function struct<
    Fields extends Record<
        string,
        | Field<unknown, string, Partial<FieldsValue<Fields>>, unknown>
        | StructLike<unknown>
    >,
    Extra extends Record<PropertyKey, unknown> | undefined = undefined,
    PostDeserialize = FieldsValue<Fields> & ExtraToIntersection<Extra>,
>(
    fields: Fields,
    options: {
        littleEndian: boolean;
        extra?: (Extra & ThisType<FieldsValue<Fields>>) | undefined;
        postDeserialize?:
            | ((
                  this: FieldsValue<Fields> & ExtraToIntersection<Extra>,
                  value: FieldsValue<Fields> & ExtraToIntersection<Extra>,
              ) => PostDeserialize)
            | undefined;
    },
): Struct<Fields, Extra, PostDeserialize> {
    const fieldList = Object.entries(fields);

    let size = 0;
    let byob = true;
    for (const [, field] of fieldList) {
        size += field.size;
        if (byob && field.type !== "byob") {
            byob = false;
        }
    }

    const littleEndian = options.littleEndian;
    const extra = options.extra
        ? Object.getOwnPropertyDescriptors(options.extra)
        : undefined;

    return {
        littleEndian,
        fields,
        extra: options.extra,

        type: byob ? "byob" : "default",
        size,
        serialize(
            source: FieldsInit<Fields>,
            bufferOrContext?: Uint8Array | StructSerializeContext,
        ): Uint8Array | number {
            const temp: Record<string, unknown> = { ...source };

            for (const [key, field] of fieldList) {
                if (key in temp && "init" in field) {
                    const result = field.init?.(temp[key], temp as never);
                    temp[key] = result;
                }
            }

            const sizes = new Array<number>(fieldList.length);