# Vega: Use values from "data" for a signal definition
**URL:** https://discuss.elastic.co/t/vega-use-values-from-data-for-a-signal-definition/140869
**Category:** Kibana
**Created:** [July 20, 2018, 10:24am UTC](https://discuss.elastic.co/t/vega-use-values-from-data-for-a-signal-definition/140869 "2018-07-20T10:24:54Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@vega\_user](https://discuss.elastic.co/u/vega_user)
#### Post date: [July 20, 2018, 10:24am UTC](https://discuss.elastic.co/t/vega-use-values-from-data-for-a-signal-definition/140869/1 "2018-07-20T10:24:55Z")
Hello everyone,
I was wondering whether it is possible to use a specific value from "data" within a signal - for instance, to define the initial value of a slider. I tried this:
```auto
"data": [
{
"name": "testvalue",
"values": [{"first": "40"}]
}
],
"signals": [
{
"name": "testslider",
"value": {"signal": "data('testvalue')[0].first"},
"bind": {
"input": "range",
"min": 0,
"max": 100,
"step": 1
}
}
]
```
But it does not work - I get [Object object] as the initial value. However, this works perfectly fine in, for instance, x-coordinate-values within marks. Is there another solution to use values from other sources within signal definitions?
Thanks,
vega\_user
---
### Author:  [@christophilus](https://discuss.elastic.co/u/christophilus)
#### Post date: [August 6, 2018, 4:08pm UTC](https://discuss.elastic.co/t/vega-use-values-from-data-for-a-signal-definition/140869/2 "2018-08-06T16:08:31Z")
Hi Anna,
I took a look into this a bit, but it's honestly a question that's probably best asked in the [Vega forum](https://groups.google.com/forum/#!forum/vega-js). I'd drop it in there, as it's not a Kibana-specific question.
That said, I wasn't able to figure out how to get the signal's value to have access to the global data structures. `"value": "datum"` Worked, but it's not what you're looking for! I don't think that you can put the value `{ "signal": ...}` Where you are. I think you need to put a direct expression there: `"value": "time('Jan 1, 2008')"` For example.
But as I said, the Vega folks should be able to answer this much better than I!
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 3, 2018, 4:08pm UTC](https://discuss.elastic.co/t/vega-use-values-from-data-for-a-signal-definition/140869/3 "2018-09-03T16:08:32Z")
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