init composable setup and folder structure

vr16x · vr16x · commit 6c3eb90e1f08 · 2026-03-27T17:14:35.000+05:30
diff --git a/bun.lock b/bun.lock
diff --git a/package.json b/package.json
@@ -12,7 +12,8 @@
   "devDependencies": {
     "@biomejs/biome": "2.4.9",
     "@changesets/cli": "2.30.0",
-    "@types/bun": "latest"
+    "@types/bun": "latest",
+    "vitest": "^4.1.2"
   },
   "peerDependencies": {
     "typescript": "^5",
diff --git a/src/core/contract.ts b/src/core/contract.ts
diff --git a/src/core/contract/contract.test.ts b/src/core/contract/contract.test.ts
@@ -0,0 +1,78 @@
+import { describe, expect, it } from 'vitest';
+import { getAddress } from 'viem';
+import { contract } from './contract';
+import { publicClient } from '../../test/utils';
+
+// Uniswap V3 Factory on Base Sepolia
+const UNISWAP_V3_FACTORY = getAddress('0x4752ba5DBc23f44D87826276BF6Fd6b1C372aD24');
+const UNISWAP_V3_FACTORY_ABI = [
+  {
+    name: 'owner',
+    type: 'function',
+    stateMutability: 'view',
+    inputs: [],
+    outputs: [{ name: '', type: 'address' }],
+  },
+  {
+    name: 'feeAmountTickSpacing',
+    type: 'function',
+    stateMutability: 'view',
+    inputs: [{ name: 'fee', type: 'uint24' }],
+    outputs: [{ name: '', type: 'int24' }],
+  },
+  {
+    name: 'getPool',
+    type: 'function',
+    stateMutability: 'view',
+    inputs: [
+      { name: 'tokenA', type: 'address' },
+      { name: 'tokenB', type: 'address' },
+      { name: 'fee', type: 'uint24' },
+    ],
+    outputs: [{ name: 'pool', type: 'address' }],
+  },
+] as const;
+
+const USDC = getAddress('0x036CbD53842c5426634e7929541eC2318f3dCF7e');
+const WETH = getAddress('0x4200000000000000000000000000000000000006');
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+describe('contract — Uniswap V3 Factory (Base Sepolia)', () => {
+  const factory = contract(publicClient, UNISWAP_V3_FACTORY, UNISWAP_V3_FACTORY_ABI);
+
+  it('stores the correct address and abi', () => {
+    expect(factory.address).toBe(UNISWAP_V3_FACTORY);
+    expect(factory.abi).toBe(UNISWAP_V3_FACTORY_ABI);
+  });
+
+  it('read(owner) returns a valid address', async () => {
+    const owner = await factory.read('owner', []);
+    expect(owner).toMatch(/^0x[0-9a-fA-F]{40}$/);
+  });
+
+  it('read(feeAmountTickSpacing) returns 60 for the 0.3% fee tier', async () => {
+    const tickSpacing = await factory.read('feeAmountTickSpacing', [3000]);
+    expect(tickSpacing).toBe(60);
+  });
+
+  it('read(feeAmountTickSpacing) returns 200 for the 1% fee tier', async () => {
+    const tickSpacing = await factory.read('feeAmountTickSpacing', [10000]);
+    expect(tickSpacing).toBe(200);
+  });
+
+  it('read(getPool) returns an address for USDC/WETH 0.3% pool', async () => {
+    const pool = await factory.read('getPool', [USDC, WETH, 3000]);
+    expect(pool).toMatch(/^0x[0-9a-fA-F]{40}$/);
+  });
+
+  it('read(getPool) is symmetric — same pool regardless of token order', async () => {
+    const [poolA, poolB] = await Promise.all([
+      factory.read('getPool', [USDC, WETH, 3000]),
+      factory.read('getPool', [WETH, USDC, 3000]),
+    ]);
+    expect(poolA).toBe(poolB);
+  });
+});
diff --git a/src/core/contract/contract.ts b/src/core/contract/contract.ts
@@ -0,0 +1,21 @@
+import type { Abi } from 'abitype';
+import type { Address, Chain, PublicClient, Transport } from 'viem';
+import type { ContractInstance } from './types';
+
+export function contract<
+  const TAbi extends Abi | readonly unknown[],
+  TTransport extends Transport = Transport,
+  TChain extends Chain | undefined = Chain | undefined,
+>(
+  publicClient: PublicClient<TTransport, TChain>,
+  address: Address,
+  abi: TAbi,
+): ContractInstance<TAbi> {
+  return {
+    address,
+    abi,
+    read(functionName, args) {
+      return publicClient.readContract({ abi, address, functionName, args });
+    },
+  };
+}
diff --git a/src/core/contract/index.ts b/src/core/contract/index.ts
@@ -0,0 +1,2 @@
+export * from './contract';
+export * from './types';
diff --git a/src/core/contract/types.ts b/src/core/contract/types.ts
@@ -0,0 +1,14 @@
+import type { Abi } from 'abitype';
+import type { Address, ContractFunctionArgs, ContractFunctionName, ContractFunctionReturnType } from 'viem';
+
+export interface ContractInstance<TAbi extends Abi | readonly unknown[]> {
+  readonly address: Address;
+  readonly abi: TAbi;
+  read<
+    TFunctionName extends ContractFunctionName<TAbi, 'pure' | 'view'>,
+    const TArgs extends ContractFunctionArgs<TAbi, 'pure' | 'view', TFunctionName>,
+  >(
+    functionName: TFunctionName,
+    args: TArgs,
+  ): Promise<ContractFunctionReturnType<TAbi, 'pure' | 'view', TFunctionName, TArgs>>;
+}
diff --git a/src/core/encoding/encoding.ts b/src/core/encoding/encoding.ts
diff --git a/src/core/encoding/index.ts b/src/core/encoding/index.ts
@@ -0,0 +1,2 @@
+export * from './encoding';
+export * from './types';
diff --git a/src/core/encoding/types.ts b/src/core/encoding/types.ts
@@ -0,0 +1 @@
+// Encoding types
diff --git a/src/core/index.ts b/src/core/index.ts
@@ -1,4 +1,3 @@
-export * from './encoding';
-export * from './types';
 export * from './token';
 export * from './contract';
+export * from './encoding';
diff --git a/src/core/token.ts b/src/core/token.ts
diff --git a/src/core/token/index.ts b/src/core/token/index.ts
@@ -0,0 +1,2 @@
+export * from './token';
+export * from './types';
diff --git a/src/core/token/token.test.ts b/src/core/token/token.test.ts
@@ -0,0 +1,94 @@
+import { describe, expect, it } from 'vitest';
+import { getAddress } from 'viem';
+import { ERC20Token, NativeToken } from './token';
+import { publicClient } from '../../test/utils';
+
+// Well-known Base Sepolia token addresses
+const USDC_ADDRESS = getAddress('0x036CbD53842c5426634e7929541eC2318f3dCF7e');
+const WETH_ADDRESS = getAddress('0x4200000000000000000000000000000000000006');
+
+// Base Sepolia Uniswap V3 router — known to have a USDC allowance set
+const UNISWAP_V3_ROUTER = getAddress('0x94cC0AaC535CCDB3C01d6787D6413C739ae12bc4');
+
+// WETH contract itself always holds ETH (it IS the wrapped ETH)
+const WETH_CONTRACT = WETH_ADDRESS;
+
+// ---------------------------------------------------------------------------
+// ERC20Token — USDC
+// ---------------------------------------------------------------------------
+
+describe('ERC20Token — USDC (Base Sepolia)', () => {
+  const usdc = ERC20Token(publicClient, USDC_ADDRESS);
+
+  it('stores the correct address', () => {
+    expect(usdc.address).toBe(USDC_ADDRESS);
+  });
+
+  it('read(symbol) returns "USDC"', async () => {
+    const symbol = await usdc.read('symbol', []);
+    expect(symbol).toBe('USDC');
+  });
+
+  it('read(decimals) returns 6', async () => {
+    const decimals = await usdc.read('decimals', []);
+    expect(decimals).toBe(6);
+  });
+
+  it('read(totalSupply) returns a positive bigint', async () => {
+    const supply = await usdc.read('totalSupply', []);
+    expect(typeof supply).toBe('bigint');
+    expect(supply > 0n).toBe(true);
+  });
+
+  it('read(balanceOf) returns a bigint for any address', async () => {
+    const balance = await usdc.read('balanceOf', [UNISWAP_V3_ROUTER]);
+    expect(typeof balance).toBe('bigint');
+  });
+
+  it('read(allowance) returns a bigint for any owner + spender pair', async () => {
+    const allowance = await usdc.read('allowance', [USDC_ADDRESS, UNISWAP_V3_ROUTER]);
+    expect(typeof allowance).toBe('bigint');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// ERC20Token — WETH
+// ---------------------------------------------------------------------------
+
+describe('ERC20Token — WETH (Base Sepolia)', () => {
+  const weth = ERC20Token(publicClient, WETH_ADDRESS);
+
+  it('read(symbol) returns "WETH"', async () => {
+    const symbol = await weth.read('symbol', []);
+    expect(symbol).toBe('WETH');
+  });
+
+  it('read(decimals) returns 18', async () => {
+    const decimals = await weth.read('decimals', []);
+    expect(decimals).toBe(18);
+  });
+
+  it('read(totalSupply) returns a bigint', async () => {
+    const supply = await weth.read('totalSupply', []);
+    expect(typeof supply).toBe('bigint');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// NativeToken
+// ---------------------------------------------------------------------------
+
+describe('NativeToken (Base Sepolia)', () => {
+  const native = NativeToken(publicClient);
+
+  it('getBalance returns a bigint', async () => {
+    const balance = await native.getBalance(WETH_CONTRACT);
+    expect(typeof balance).toBe('bigint');
+  });
+
+  it('getBalance of the WETH contract is positive', async () => {
+    // The WETH contract always holds ETH equal to its totalSupply
+    const balance = await native.getBalance(WETH_CONTRACT);
+    expect(balance > 0n).toBe(true);
+  });
+});
diff --git a/src/core/token/token.ts b/src/core/token/token.ts
@@ -0,0 +1,27 @@
+import { erc20Abi } from 'viem';
+import type { Address, Chain, PublicClient, Transport } from 'viem';
+import type { ERC20TokenInstance, NativeTokenInstance } from './types';
+
+export function ERC20Token<
+  TTransport extends Transport = Transport,
+  TChain extends Chain | undefined = Chain | undefined,
+>(publicClient: PublicClient<TTransport, TChain>, address: Address): ERC20TokenInstance {
+  return {
+    address,
+    abi: erc20Abi,
+    read(functionName, args) {
+      return publicClient.readContract({ abi: erc20Abi, address, functionName, args });
+    },
+  };
+}
+
+export function NativeToken<
+  TTransport extends Transport = Transport,
+  TChain extends Chain | undefined = Chain | undefined,
+>(publicClient: PublicClient<TTransport, TChain>): NativeTokenInstance {
+  return {
+    getBalance(address) {
+      return publicClient.getBalance({ address });
+    },
+  };
+}
diff --git a/src/core/token/types.ts b/src/core/token/types.ts
@@ -0,0 +1,20 @@
+import { erc20Abi } from 'viem';
+import type { Address, ContractFunctionArgs, ContractFunctionName, ContractFunctionReturnType } from 'viem';
+
+export type ERC20Abi = typeof erc20Abi;
+
+export interface ERC20TokenInstance {
+  readonly address: Address;
+  readonly abi: ERC20Abi;
+  read<
+    TFunctionName extends ContractFunctionName<ERC20Abi, 'pure' | 'view'>,
+    const TArgs extends ContractFunctionArgs<ERC20Abi, 'pure' | 'view', TFunctionName>,
+  >(
+    functionName: TFunctionName,
+    args: TArgs,
+  ): Promise<ContractFunctionReturnType<ERC20Abi, 'pure' | 'view', TFunctionName, TArgs>>;
+}
+
+export interface NativeTokenInstance {
+  getBalance(address: Address): Promise<bigint>;
+}
diff --git a/src/core/types.ts b/src/core/types.ts
diff --git a/src/test/utils.ts b/src/test/utils.ts
@@ -0,0 +1,10 @@
+import { createPublicClient, fallback, http } from 'viem';
+import { baseSepolia } from 'viem/chains';
+
+export const publicClient = createPublicClient({
+  chain: baseSepolia,
+  transport: fallback([
+    http('https://sepolia.base.org'),
+    http('https://base-sepolia.blockpi.network/v1/rpc/public'),
+  ]),
+});

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+export * from './contract';`
	`2`	`+export * from './types';`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+export * from './encoding';`
	`2`	`+export * from './types';`