I'm trying to get this list in the view, but this doesn't display any items
render: function() {
var list = this.state.list;
console.log('Re-rendered');
return(
<ul>
{list.map(function(object, i){
<li key='{i}'>{object}</li>
})}
</ul>
)
}
list
is first set to null, but then I reload it with AJAX. This on the other hand works
<ul>
{list.map(setting => (
<li>{setting}</li>
))}
</ul>
This is my whole component as it stands:
var Setting = React.createClass({
getInitialState: function(){
return {
'list': []
}
},
getData: function(){
var that = this;
var myHeaders = new Headers();
var myInit = { method: 'GET',
headers: myHeaders,
mode: 'cors',
cache: 'default' };
fetch('/list/',myInit)
.then(function(response){
var contentType = response.headers.get("content-type");
if(contentType && contentType.indexOf("application/json") !== -1) {
return response.json().then(function(json) {
that.setState({'list':json.settings});
});
} else {
console.log("Oops, we haven't got JSON!");
}
})
.catch(function(error) {
console.log('There has been a problem with your fetch operation: ' + error.message);
});;
},
componentWillMount: function(){
this.getData();
},
render: function() {
var list = this.state.list;
return(
<ul>
{list.map(function(object, i){
<li key={i}>{object}</li>
})}
</ul>
)
}
});
You are missing your return statement
{list.map(function(object, i){
return <li key={i}>{object}</li>
})}
this works
<ul>
{list.map(setting => (
<li>{setting}</li>
))}
</ul>
because anything within ()
is returned automatically when using an arrow function but the previous example was using {}
which requires a return statement.
When should I use `return` in es6 Arrow Functions? this will give you more context around when and when not to use a return statement with arrow functions.
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