Mapping array value in API response for conditional check - reactjs

Question

I have an api which loads a response with an array value I need to map, in order to both check if available, and if so, use the id value of the offers to display later. I'm currently able to simply get the available option, but need to be able to map down to the offers and grab the id value within the FETCH OFFER DETAILS fetchContent.
API RESPONSE
{
"available": true,
"offers": [
{
"days_free": 30,
"id": 1,
}
]
}
React Component
class CancelOffer extends React.Component {
constructor (props) {
super(props)
this.state = {
user: []
}
this.processData = this.processData.bind(this)
this.cancelAccount = this.cancelAccount.bind(this)
this.acceptPromo = this.acceptPromo.bind(this)
}
componentDidMount () {
this.fetchContent(this.processData)
}
/**
* Fetch offer details
*/
fetchContent (cb) {
superagent
.get('/api/user/offers')
.then(function(res) {
/**
* If res.body.available === true, get offers.id and use in
acceptPromo.
* Else if not true, redirect to
.then(this.props.setStep(ACCEPTANCE))
*/
if(res.body.available){
const offerCode = res.body.offers[0].id
alert(offerCode)
} else {
this.props.setStep(ACCEPTANCE)
}
})
}
/**
* Set state after user have been fetched
* #param data
*/
processData (data) {
this.setState({
user: data.body.offers
})
}
/**
* Send accept promo offer code
*/
acceptPromo (e) {
e.preventDefault()
superagent
.post('/api/user/offers')
.send({
offerId: offerCode <==THIS NEEDS TO COME FROM THE API RESPONSE
})
.then(this.props.setStep(ACCEPTANCE))
}
render () {
const content = this.props.config.contentStrings
const daysFree = this.state.user.map((daysFree, i) => {
return (
<span>{daysFree.days_free}</span>
)
})
return (
<div className='offer'>
<h2 className='offer-heading md'>Heading</h2>
<p className='offer-subpara'>sub paragraph {daysFree}</p>
<div className='footer-links'>
<a onClick={this.acceptPromo} className='btn btn--primary btn--lg'>accept promo</a>
<a onClick={this.cancelAccount} className='cancel-link'>cancel</a>
</div>
</div>
)
}
}
export default CancelOffer

Answer 1

EDIT - ANSWER:
I needed to set the promo code in state
fetchContent (cb) {
superagent
.get('/api/user/offers')
.then((res) => {
if(res.body.available){
this.setState({
offerId: res.body.offers[0].id
})
} else {
this.props.setStep(OFFER)
}
})
}
and pass it to the accept promo
acceptPromo (e) {
e.preventDefault()
const { offerId } = this.state
superagent
.post('/api/user/offers')
.send({offerId})
.then(this.props.setStep(ACCEPTANCE))
}