#Types Harness

This example is a Soroban types harness. It demonstrates how to encode and invoke different types of SCVal you need from a client, including user defined structs and enums, so wallet and tooling code can learn from real payloads. The contract exposes one function per type, the TypeScript call script simulates first, prints the returned SCVal type and value, and auto funds the source on testnet with friendbot if needed.

Requirements

• Deno - Modern runtime for JavaScript and TypeScript
• Stellar CLI - The command line interface to Stellar smart contracts

Setup

1. Copy the environment configuration:

cp .env.example .env

The .env is configured by default to use testnet. Feel free to adjust its parameters to use a different target network.

2. Build the contract

stellar contract build

3. Deploy the contract:

deno task deploy

Usage

Use the following command to simulate an invocation to a given function of the contract:

deno task call <function name>

For example, to simulate an invocation to vec_address run:

deno task call vec_address

The script under ./typescript/call.ts will assemble and parametrize a transaction to invoke this function, then simulate and output the details of the returned value.

The contract source lives at contracts/types-harness/src/lib.rs. Below are the exported contract functions you can invoke with deno task call <function name>.

• void(env)
• bool(env, bool) -> bool
• u32(env, u32) -> u32
• i32(env, i32) -> i32
• u64(env, u64) -> u64
• i64(env, i64) -> i64
• timepoint(env, Timepoint) -> Timepoint
• duration(env, Duration) -> Duration
• u128(env, u128) -> u128
• i128(env, i128) -> i128
• u256(env, U256) -> U256
• i256(env, I256) -> I256
• bytes(env, Bytes) -> Bytes
• string(env, String) -> String
• symbol(env, Symbol) -> Symbol
• address(env, Address) -> Address
• vec_i128(env, Vec) -> Vec
• vec_address(env, Vec) -> Vec
• map_sym_i128(env, Map<Symbol, i128>) -> Map<Symbol, i128>
• map_sym_vec_addr(env, Map<Symbol, Vec>) -> Map<Symbol, Vec>
• any(env, Val) -> Val
• vec_any(env, Vec) -> Vec
• map_sym_any(env, Map<Symbol, Val>) -> Map<Symbol, Val>
• user(env, User) -> User
• choice(env, Choice) -> Choice
• vec_user(env, Vec) -> Vec
• map_addr_user(env, Map<Address, User>) -> Map<Address, User>
• optionu32(env, Option) -> Option ⚡ _Requires mode arg
• optionaddress(env, Option) -> Option ⚡ _Requires mode arg
• optionuser(env, Option) -> Option ⚡ _Requires mode arg
• nestedtype(env, NestedType) -> NestedType ⚡ _Requires depth and width args
• flattennested_type(env, NestedType) -> Vec ⚡ _Requires depth and width args
• fail(env, bool)

Functions with Arguments

Option functions require a mode argument:

deno task call option_u32 <mode>
deno task call option_address <mode>
deno task call option_user <mode>

• mode: Either 'some' or 'none' to test Some(value) or None variants

Nested functions require depth and width arguments:

deno task call nested_type <depth> <width>
deno task call flatten_nested_type <depth> <width>

• depth: How deep the nesting goes (e.g., 2 = nested.nested)
• width: How many items in each array layer (e.g., 3 = 3 items per level)

Examples:

# Option examples
deno task call option_u32 some
deno task call option_address none

# Nested examples
deno task call nested_type 2 3
deno task call flatten_nested_type 1 4

Each function is a simple identity/echo for the specified type and is intended for testing how different SCVal types are encoded and returned.