> For the complete documentation index, see [llms.txt](https://docs.polarity.io/integrations/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.polarity.io/integrations/build-an-integration/main/dolookup.md).

# doLookup

Required function which takes entities from the user and returns enriched results

## Summary

**required** `function doLookup(entities, options, callback)`

| **Parameters** | Description                                                                                       |
| -------------- | ------------------------------------------------------------------------------------------------- |
| entities       | An array of entity objects seen on the requesting user's screen                                   |
| options        | An options object with key value pairs representing the requesting user's options and their value |
| callback       | A Node.js style callback which should return an array of `resultObjects`                          |

{% hint style="info" %}
For a quick overview of the `doLookup` method please see the [Quick Start Guide](/integrations/quick-start/quick-start-guide.md).
{% endhint %}

The `doLookup` method is main entry point into your main module. This method is currently the only function that must be exported from your main module (`integration.js`). The method receives a list of entities that appeared on the user's screen and the returns contextual data related to those entities.

## Parameters

The following is an explanation of the `doLookup` parameters

### entities

The `entities` parameter is an array of [Entity Objects](/integrations/build-an-integration/main/dolookup/entity-objects.md). Each entity object contains a range of boolean flags that can be used to determine the type of the entity. In addition, every entity object contains a `value`, `type`, and `types` property.

For additional information please see the section on [Entity Objects](/integrations/build-an-integration/main/dolookup/entity-objects.md)

Sample entities array

```javascript
  [{
     // entity object
     type: 'IPv4',
     types: ['IP', IPv4'],
     isIP: true,
     isIPv4: true,
     isIPv6: false,
     isPrivateIP: true,
     IPType: 'IPv4',
     isDomain: false,
     isHash: false,
     isMD5: false,
     isSHA1: false,
     isSHA256: false,
     hashType: '',
     isEmail: false,
     isURL: false,
     value: '192.168.0.1',
     IPLong: 939655937,
     channels: []
 }]
```

### options

The second parameter to the `doLookup` method is the `options` object which contains the values for the integration options as set in the integration `config.js`. Note that for per-user settings the value in the `options` object will reflect the value of the user requesting the lookup.

The key in the `options` object is the same value of the `key` property set in the integration `config.js` file.

{% code title="Sample Options Object" %}

```javascript
{
    "apiKey": "lkasjdioajsdoij12lk3j1lk23j12",
    "lookupHashes": true,
    "throttleLookups": false
}
```

{% endcode %}

### callback(error, results)

```
@param callback
@type Function
@param {String | Object} error
@param {Array} results
```

The callback must be called before execution of the `doLookup` method completes. The callback accepts two parameters.

The first parameter is an error which can either be a string literal or a JSON API error object. In the case of a string literal the returned string is displayed as an error in the notification window as well as tracked as an error in the integration

```javascript
//callback parameters
callback(error, results);
```

{% hint style="info" %}
If you have no error to return you should return `null` for the `error` parameter.
{% endhint %}

Please see below for additional information on error objects and result objects.

##