> ## Documentation Index
> Fetch the complete documentation index at: https://docs.reducto.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Split

> Split documents into sections using the JavaScript SDK

The `split.run()` method divides documents into sections based on descriptions you provide. You define what sections to look for, and Split identifies which pages belong to each section.

***

## Basic Usage

```javascript theme={null}
import Reducto from 'reductoai';
import fs from 'fs';

const client = new Reducto();

// Upload
const upload = await client.upload({ 
  file: fs.createReadStream("document.pdf") 
});

// Split the document - split_description is required
const result = await client.split.run({
  input: upload.file_id,
  split_description: [
    { name: "Summary", description: "Executive summary or overview section" },
    { name: "Financial Data", description: "Tables with financial figures" },
    { name: "Notes", description: "Footnotes or additional notes" }
  ]
});

// Access splits
for (const split of result.result.splits) {
  console.log(`Section: ${split.name}`);
  console.log(`Pages: ${split.pages}`);  // Array of page numbers
  console.log(`Confidence: ${split.conf}`);  // "high" or "low"
}
```

***

## Method Signatures

### Synchronous Split

```typescript theme={null}
split.run(params: {
  input: string | Upload;
  split_description: Array<SplitCategory>;
  parsing?: ParseOptions;
  settings?: {
    table_cutoff?: "truncate" | "preserve";
  };
  split_rules?: string;
}, options?: RequestOptions): Promise<SplitResponse>
```

### Asynchronous Split

```typescript theme={null}
split.runJob(params: {
  input: string | Upload;
  split_description: Array<SplitCategory>;
  async?: ConfigV3AsyncConfig;
  parsing?: ParseOptions;
  settings?: {
    table_cutoff?: "truncate" | "preserve";
  };
  split_rules?: string;
}, options?: RequestOptions): Promise<SplitRunJobResponse>
```

***

## Split Description

The `split_description` parameter is required. Each entry defines a section to find:

```javascript theme={null}
const splitDescription = [
  {
    name: "Cover Page",
    description: "Title page with company logo and report title"
  },
  {
    name: "Table of Contents",
    description: "Page listing all sections with page numbers"
  },
  {
    name: "Financial Statements",
    description: "Balance sheet, income statement, and cash flow tables"
  }
];

const result = await client.split.run({
  input: upload.file_id,
  split_description: splitDescription
});
```

### With Partition Key

Use `partition_key` when a section type repeats multiple times and you want to group by a specific identifier:

```javascript theme={null}
const result = await client.split.run({
  input: upload.file_id,
  split_description: [
    {
      name: "Invoice",
      description: "Individual invoice with line items and total",
      partition_key: "invoice_number"  // Group pages by invoice number
    }
  ]
});
```

***

## Configuration Examples

### Split Rules

The `split_rules` parameter is a natural language prompt that controls how pages are classified:

```javascript theme={null}
const result = await client.split.run({
  input: upload.file_id,
  split_description: [
    { name: "Summary", description: "Executive summary" },
    { name: "Details", description: "Detailed content" }
  ],
  split_rules: "Pages can belong to multiple sections if they contain content from both."
});
```

### Table Settings

```javascript theme={null}
const result = await client.split.run({
  input: upload.file_id,
  split_description: [
    { name: "Tables", description: "Data tables" }
  ],
  settings: {
    table_cutoff: "preserve"  // Keep all table rows (default: "truncate")
  }
});
```

***

## Response Structure

```javascript theme={null}
const result = await client.split.run({ ... });

// Access splits
for (const split of result.result.splits) {
  console.log(split.name);       // string: Section name you defined
  console.log(split.pages);      // number[]: Page numbers (1-indexed)
  console.log(split.conf);       // string: "high" or "low"
  console.log(split.partitions); // array | null: Sub-sections when partition_key is used
}
```

***

## Next Steps

* Learn about [split configuration options](/configs/split/configuration)
* Check out [parsing split sections](/sdk/javascript/parse) for further processing