Using REST, I am retrieving an object(JSON format) which is to be converted to an array so that it can be inserted into a table.
This is done in the rendering function of React.
The input is updated every N minutes from the back-end.
How do I convert an object to an array?
I need only the values, not the keys, since the keys are already present as column values beforehand in the table itself.
You can use Object#values (ECMAScript 2017), but it's not supported by IE (see browser's compatibility).
Note: The ECMAScript 6 specification defines in which order the properties of an object should be traversed. This blog post explains the details.
const map = { a: 1, b: 2, c: 3 };
const result = Object.values(map);
console.log(result);If you need to support IE, you can use Object#keys with Array#map:
const map = { a: 1, b: 2, c: 3 };
const result = Object.keys(map).map((key) => map[key]);
console.log(result);
var tableDataMap = this.props.data.dataMap; and need to pass it down to a new const as yours above, I presume? Along those lines.
I am not sure by map you mean the Map object or an ordinary JS object. However, just for variety I would like to mention that the Map objects are mostly (probably always) stringified like JSON.stringify([...myMap]). So if you happen to receive a Map object in JSON data may be you should do something like;
var myMap = new Map().set(1,"hey").set(2,"you"),
mapData = JSON.stringify([...myMap]),
values = JSON.parse(mapData).map(d => d[1]);
console.log("mapData:",mapData);
console.log("values:",values);You can set initial value as array firstly. See this example:
const [conversations, setConversations] = useState([]); // fianal data is array
useEffect(() => {
const fetchConversations = async () => {
const res = await axios.get("/conversations/" + user._id);
setConversations(res.data);
};
fetchConversations();
}, [user._id]);
res.data convert to array by using useState([]) as initial value and convert to object by using useState({}).
And
return( {conversations.map((conv) => ( ))} )
You can set initial value as array firstly. See this example:
const [conversations, setConversations] = useState([]); // fianal data is array
useEffect(() => {
const fetchConversations = async () => {
const res = await axios.get("/conversations/" + user._id);
setConversations(res.data);
};
fetchConversations();
}, [user._id]);
res.data convert to array by using useState([]) as initial value and convert to object by using useState({}).
And map this array:
return (
<>
{conversations.map((conv) =>
(<Conversations key={conv._id} conversation={conv} />))}
</>
)