Can't get `fetch()` working in React Native - react-native

Question

Any idea why I can't get fetch() working in React Native? Full code is here on RN Play:
https://rnplay.org/apps/L80w2w
Here's a working ReactJS Fiddle that I'm trying to get working in React Native: https://jsfiddle.net/ssorallen/fEsYt/
componentDidMount: function() {
var _this = this;
var queryParams = "fn" + Date.now() + '/';
var queryUrl = "https://www.reddit.com/reddits.json?jsonp=" + queryParams;
fetch(queryUrl)
.then(response => response.json())
.then(responseData => this._handleResponse(responseData.data.children))
.catch(error => this.setState({
isLoading: false,
errorMessage: 'Something bad happened - loading navigationItems: \n' + error
}));
},
_handleResponse(results) {
this.setState({ isLoading: false });
if (results.length > 0) {
this.setState({
navigationItems: results
});
} else {
this.setState({ errorMessage: "Can't find JSON." });
}
},

Answer 1

You are attempting to call the Reddit using the JSONP technique, which is not necessary, as React Native does not impose the Same-Origin security policy as browsers do.
If you remove the ?jsonp=" + queryParams parameter from your URL, the requests should work.

Answer 2

completed = (id) => {
var details = {
'id': id,
};
var formBody = [];
for (var property in details) {
var encodedKey = encodeURIComponent(property);
var encodedValue = encodeURIComponent(details[property]);
formBody.push(encodedKey + "=" + encodedValue);
}
formBody = formBody.join("&");
fetch(markcompleted, {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/x-www-form-urlencoded'
},
body: formBody
})
.then((response) => response.json())
.then((responseJson) => {
console.log(responseJson, 'res JSON');
if (responseJson.status == "success") {
console.log(this.state);
alert("your todolist is completed!!");
}
})
.catch((error) => {
console.error(error);
});
};
#change post into get