> For the complete documentation index, see [llms.txt](https://docs.viesus.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.viesus.com/reference/node.js-module/api-reference.md).

# API Reference

{% hint style="info" %}
**Linux Only**

The VIESUS Node.js module is available on **Linux only**.
{% endhint %}

***

## Import

```js
const viesus = require('viesus');
```

***

## `new viesus.MyViesusObject(guid)`

Creates and initializes a VIESUS enhancer instance. Create one object per worker thread and **reuse it** across multiple `Enhance()` calls — initialization is expensive.

| Parameter | Type     | Description              |
| --------- | -------- | ------------------------ |
| `guid`    | `string` | Your VIESUS license GUID |

```js
const viesusObj = new viesus.MyViesusObject('4e8f35ab-7f72-4b1e-a1fd-2b5e9c58e9d3');
```

***

## `viesusObj.Enhance(fromPath, toPath, iniPath, resPath)`

Enhances a single image. **Synchronous** — must be called from a worker thread, not the main thread.

<table><thead><tr><th width="129">Parameter</th><th width="109.800048828125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>fromPath</code></td><td><code>string</code></td><td>Absolute path to the input image</td></tr><tr><td><code>toPath</code></td><td><code>string</code></td><td>Absolute path for the enhanced output image</td></tr><tr><td><code>iniPath</code></td><td><code>string</code></td><td>Absolute path to the <code>viesusini.json</code> configuration file</td></tr><tr><td><code>resPath</code></td><td><code>string</code></td><td>Absolute path for the result JSON output file</td></tr></tbody></table>

**Returns:** `number`

* `> 0` — success; value is processing time in milliseconds
* `< 0` — error; see [error codes](#error-codes)

```js
const result = viesusObj.Enhance(fromPath, toPath, iniPath, resPath);
if (result > 0) {
  console.log(`Enhanced in ${result}ms`);
} else {
  console.error(`Error: ${result}`);
}
```

***

## Error codes

<table><thead><tr><th width="154">Code</th><th>Description</th></tr></thead><tbody><tr><td><code>-1</code></td><td>Init failed</td></tr><tr><td><code>-2</code></td><td>GUID wrong</td></tr><tr><td><code>-3</code></td><td>Internal error</td></tr><tr><td><code>-4</code></td><td>Loading image not possible</td></tr><tr><td><code>-5</code></td><td>Can't open file</td></tr><tr><td><code>-6</code></td><td>File not found</td></tr><tr><td><code>-7</code></td><td>File is empty</td></tr><tr><td><code>-8</code></td><td>Memory open internal error</td></tr><tr><td><code>-9</code></td><td>Enhancement failed — contact <a href="mailto:info@viesus.com">info@viesus.com</a></td></tr><tr><td><code>-10</code></td><td>Parameter file not found</td></tr><tr><td><code>-11</code></td><td>Parameter file empty</td></tr><tr><td><code>-12</code></td><td>Output format not supported</td></tr><tr><td><code>-13</code></td><td>Error writing result file</td></tr><tr><td><code>-126</code></td><td>Enhancement failed — image was already enhanced</td></tr><tr><td><code>-378</code></td><td>Wrong GUID</td></tr><tr><td><code>&#x3C; -18</code></td><td>Internal error — contact <a href="mailto:info@viesus.com">info@viesus.com</a></td></tr></tbody></table>

***

## Result JSON

When `WriteResultFiles: 1` is set in `viesusini.json`, a JSON file is written to `resPath` after each enhancement with per-image processing details:

```json
{
  "brightCorrStrength": 0.011,
  "colorCorrStrength": 0.083,
  "contrCorrStrength": 0.0,
  "fdApplied": 1,
  "ggaApplied": 0,
  "globShpApplied": 0,
  "glowStrength": 0.0,
  "ieApplied": 1,
  "isArtificial": 0,
  "isMonochrome": 0,
  "locShpApplied": 1,
  "noiseStrength": 0.0,
  "nrApplied": 0,
  "rerApplied": 1,
  "rszApplied": 1,
  "rszSRApplied": 0,
  "arApplied": 0,
  "bgApplied": 0,
  "staApplied": 0
}
```

<table><thead><tr><th width="202.5999755859375">Field</th><th width="84.7999267578125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>brightCorrStrength</code></td><td>float</td><td>Applied brightness correction strength</td></tr><tr><td><code>colorCorrStrength</code></td><td>float</td><td>Applied color correction strength</td></tr><tr><td><code>fdApplied</code></td><td>int</td><td><code>1</code> if face detection ran</td></tr><tr><td><code>ieApplied</code></td><td>int</td><td><code>1</code> if image enhancement ran</td></tr><tr><td><code>isArtificial</code></td><td>int</td><td><code>1</code> if image was classified as artificial/synthetic</td></tr><tr><td><code>isMonochrome</code></td><td>int</td><td><code>1</code> if image was detected as monochrome</td></tr><tr><td><code>locShpApplied</code></td><td>int</td><td><code>1</code> if local sharpening was applied</td></tr><tr><td><code>rszApplied</code></td><td>int</td><td><code>1</code> if resizing was applied</td></tr><tr><td><code>rszSRApplied</code></td><td>int</td><td><code>1</code> if AI upscaling was used for resize</td></tr><tr><td><code>arApplied</code></td><td>int</td><td><code>1</code> if artifact removal was applied</td></tr><tr><td><code>bgApplied</code></td><td>int</td><td><code>1</code> if background handling was applied</td></tr></tbody></table>

***

## Thread pool pattern

The recommended production pattern uses `node-worker-threads-pool`:

```js
// worker.js
const { parentPort, workerData } = require('worker_threads');
const viesus = require('viesus');

const viesusObj = new viesus.MyViesusObject(workerData);

parentPort.on('message', (job) => {
  const result = viesusObj.Enhance(job.fromPath, job.toPath, job.iniPath, job.resPath);
  parentPort.postMessage(result);
});
```

```js
// main.js
const { StaticPool } = require('node-worker-threads-pool');

const pool = new StaticPool({
  size: Number(process.env.UV_THREADPOOL_SIZE),
  task: './worker.js',
  workerData: 'YOUR-GUID-HERE'
});

async function enhanceImage(fromPath, toPath, iniPath, resPath) {
  const result = await pool.exec({ fromPath, toPath, iniPath, resPath });
  if (result < 0) throw new Error(`VIESUS error: ${result}`);
  return result;
}
```

See [Getting Started](/reference/node.js-module/getting-started.md) for the complete example.


---

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