At the core of llm-ui is useLLMOutput. This hook takes a single chat response from an LLM and breaks it into blocks.

Blocks

useLLMOutput takes blocks and fallbackBlock as arguments.

• blocks is an array of block configurations that useLLMOutput attempts to match against the LLM output.
• fallbackBlock is used for sections of the chat response when no other block matches.

We could pass:

• blocks: [codeBlock] which matches codeblock starting with ```.
• fallbackBlock: markdownBlock which assumes anything else is markdown .

useLLMOutput will then break the chat response into code and markdown blocks:

## Python
```python
def hello_llm_ui():
  print("Hello llm-ui!")
```
## Typescript
```typescript
const helloLlmUi = () => {
  console.log("Hello llm-ui!");
};
```

llm-ui breaks this example into blocks:

Throtting

useLLMOutput also takes throttle as an argument. This function allows useLLMOutput to lag behind the actual LLM output.

Here is an example of llm-ui’s throttling in action:

# H1
Hi Docs

```typescript
console.log('hello')
```

# H1
Hi Docs

```typescript
console.log('hello')
```

console.log('hello')

console.log('hello')

The disadvantage of throttling is that the llm output is delayed in reaching the user.

The benefits of throttling:

• llm-ui can smooth out pauses in the LLM’s streamed output.
• Blocks can hide ‘non-user’ characters from user (e.g. ## in a markdown header).