I am having trouble reformatting an Object array in Javascript. I have an array that looks like this:
[
{
"deviceid": 42,
"x": "2022-03-26T00:00:18",
"y": 17.8,
},
{
"deviceid": 42,
"x": "2022-03-26T00:01:18",
"y": 17.8,
},
{
"deviceid": 43,
"x": "2022-03-26T00:02:18",
"y": 17.8,
{
"deviceid": 43,
"x": "2022-03-26T00:02:18",
"y": 17.8,
}]
I want to re-shape it so the new form will be one record per device id and all x and y values in the same row.
[
{
"deviceid": 42,
"x": ["2022-03-26T00:00:18","2022-03-27T00:00:18"],
"y": [17.8, 15.6],
},
{
"deviceid": 43,
"x": ["2022-03-26T00:01:18","2022-03-27T00:00:18"],
"y": [17.8, 19.1],
}]
How can I make this happen?
You can use reduce() to do the reduction of your values using a JavaScript object. After the reduction get the values of the object using Object.values().
const data = [
{
deviceid: 42,
x: "2022-03-26T00:00:18",
y: 17.8,
},
{
deviceid: 42,
x: "2022-03-26T00:01:18",
y: 15.6,
},
{
deviceid: 43,
x: "2022-03-26T00:02:18",
y: 17.8,
},
{
deviceid: 43,
x: "2022-03-26T00:02:18",
y: 19.1,
},
];
const result = data.reduce((devices, device) => {
// check if we have encountered this decive before using the deviceId
if (!devices.hasOwnProperty(device.deviceid)) {
// we have not: create an key-value pair using device ID as key and device info as value
// use an array for x and y
devices[device.deviceid] = {
deviceId: device.deviceid,
x: [device.x],
y: [device.y],
};
} else {
// we have seen this device before
// get the device value using the key (deviceId) and push new x and y values to it
const curDev = devices[device.deviceid];
curDev.x.push(device.x);
curDev.y.push(device.y);
}
// return JS object of devices for next iteration/ result
return devices;
}, {});
console.log(Object.values(result));Please note: I think the input you have provided in your question contains some errors probably from copy/ pasting as the expected output contains values that are not in the input at all. I have changed values of
yin the input to show you that output is actually what you expect.