@polareth/evmstate/docs/pages/guides/usage-examples.mdx

A TypeScript library for tracing, and visualizing EVM state changes with detailed human-readable labeling.

import { Callout } from "vocs/components";

# Examples

This guide covers a few examples of how to use the library.

<Callout type="tip">
  See the [playground](/playground) for an interactive demonstration of the output based on function calls.
</Callout>

## Monitoring ERC20 balances

:::code-group

```ts twoslash [example.ts]
// [!include ~/snippets/client-fork.ts]
// [!include ~/snippets/abi.ts]
// [!include ~/snippets/layout.ts]
// ---cut---
import { createContract } from "tevm/contract";
import { traceState, type LabeledState } from "@polareth/evmstate";

// [!include ~/snippets/erc20.ts:args]

// [!include ~/snippets/erc20.ts:approve]

// [!include ~/snippets/erc20.ts:trace-swap]

// [!include ~/snippets/erc20.ts:trace-parse]
```

```ts twoslash [client.ts]
import { createMemoryClient, http } from "tevm";
import { mainnet } from "tevm/common";

// [!include ~/snippets/client-fork.ts:client-fork-no-highlight]
```

```ts twoslash [abis.ts]
// [!include ~/snippets/abi.ts:erc20]

// [!include ~/snippets/abi.ts:simple-dex]
```


```ts twoslash [layout.ts]
// [!include ~/snippets/layout.ts:erc20]
```

:::

## Processing complex outputs


:::code-group

```ts twoslash [example.ts]
// [!include ~/snippets/abi.ts:mappings]
// [!include ~/snippets/layout.ts:mappings]
// [!include ~/snippets/client.ts]
// ---cut---
import { watchState, PathSegmentKind, type StateChange } from "@polareth/evmstate";

// [!include ~/snippets/watch-state.ts:watchState-logs-onStateChange]

// [!include ~/snippets/watch-state.ts:watchState-logs-subscribe /unsubscribe2/unsubscribe/]
```

```ts twoslash [layout.ts]
// [!include ~/snippets/layout.ts:mappings]
```

```ts twoslash [abi.ts]
// [!include ~/snippets/abi.ts:mappings]
```

```ts twoslash [client.ts]
// [!include ~/snippets/client.ts]
```

:::