# danfo. convertFunctionTotransformer
danfo.**convertFunctionTotransformer**(func)
| Parameters | Type | Description | Default |
| ---------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------- | ------- |
| **func** | Function | A valid JavaScript function to convert to a [pipe transformer.](https://nodejs.org/api/stream.html#implementing-a-transform-stream) | |
**Returns:**
> return A [pipe transformer](https://nodejs.org/api/stream.html#implementing-a-transform-stream) that applies the function to each row of object.
The **convertFunctionTotransformer** takes a function and converts it to a Nodejs stream transformer function which can be used in combination with streamCsvTransformer to incrementally transform large files.
## **Converting a function to a transformer**
{% tabs %}
{% tab title="Node" %}
```javascript
const dfd = require("danfojs-node")
/*
* A simple function that takes each row of a DataFrame and splits the
* name field.
*/
const renamer = (dfRow: DataFrame) => {
const dfModified = dfRow["Names"].map((name) => name.split(",")[0])
return dfModified
}
const transformer = dfd.convertFunctionTotransformer(renamer)
console.log(transformer)
```
{% endtab %}
{% tab title="Browser" %}
```markup
Document
```
{% endtab %}
{% endtabs %}
{% tabs %}
{% tab title="Output" %}
```
Transform {
_readableState: ReadableState {
objectMode: true,
highWaterMark: 16,
buffer: BufferList { head: null, tail: null, length: 0 },
length: 0,
pipes: [],
flowing: null,
ended: false,
endEmitted: false,
reading: false,
sync: false,
needReadable: false,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
errorEmitted: false,
emitClose: true,
autoDestroy: true,
destroyed: false,
errored: null,
closed: false,
closeEmitted: false,
defaultEncoding: 'utf8',
awaitDrainWriters: null,
writecb: null,
writechunk: null,
writeencoding: null
}
}
```
{% endtab %}
{% endtabs %}
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