I'm trying to compare the date and time to manipulate my data. I need to check which is the latest data by checking updated_at key inside object.
Below I have given the scenario.
// below is my data to be manipulat
[{
"is_latest": "",
"created_at": "2021-09-21T21:24:05.000Z",
"updated_at": "2021-09-21T17:53:29.000Z"
}, {
"is_latest": "",
"created_at": "2021-09-22T21:24:05.000Z",
"updated_at": "2021-09-22T17:53:29.000Z"
}, {
"is_latest": "",
"created_at": "2021-09-29T21:24:05.000Z",
"updated_at": "2021-09-29T17:53:29.000Z" // this is the latest data
}]
I'm trying like this, but how to use moment here to compare which is latest.
for (var i = 0; i < data.length; i++) {
if (data[i].updated_at > data[i + 1].updated_at) {
data.is_latest = "true"
}
}
But I'm not getting the expected result as below.
[{
"is_latest": "false",
"created_at": "2021-09-21T21:24:05.000Z",
"updated_at": "2021-09-21T17:53:29.000Z"
}, {
"is_latest": "false",
"created_at": "2021-09-22T21:24:05.000Z",
"updated_at": "2021-09-22T17:53:29.000Z"
}, {
"is_latest": true,
"created_at": "2021-09-29T21:24:05.000Z",
"updated_at": "2021-09-29T17:53:29.000Z"
}]
How can I do this by using map() or reduce()?
You could locate the latest date by mapping the updated_at field values and spreading them in a Math.max call. After converting the Unix epoch back into a date, you can locate it by using Array.prototype.find and set the is_latest to true.
Note: Since your dates are in ISO 8601 format, converting them back is as easy as calling Date.prototype.toISOString.
const data = [{
"is_latest": false,
"created_at": "2021-09-21T21:24:05.000Z",
"updated_at": "2021-09-21T17:53:29.000Z"
}, {
"is_latest": false,
"created_at": "2021-09-22T21:24:05.000Z",
"updated_at": "2021-09-22T17:53:29.000Z"
}, {
"is_latest": false,
"created_at": "2021-09-29T21:24:05.000Z",
"updated_at": "2021-09-29T17:53:29.000Z" // this is the latest data
}];
const latestDate = new Date(Math.max(...(data.map(({ updated_at }) =>
new Date(updated_at))))).toISOString();
data.find(({ updated_at }) => updated_at === latestDate).is_latest = true;
console.log(data);.as-console-wrapper { top: 0; max-height: 100% !important; }You should check it map and get the max date index. and then set its value to true;
var data = [
{
"is_latest": "",
"created_at": "2021-09-21T21:24:05.000Z",
"updated_at": "2021-09-21T17:53:29.000Z"
},
{
"is_latest": "",
"created_at": "2021-09-22T21:24:05.000Z",
"updated_at": "2021-09-22T17:53:29.000Z"
},
{
"is_latest": "",
"created_at": "2021-09-29T21:24:05.000Z",
"updated_at": "2021-09-29T17:53:29.000Z"
},
{
"is_latest": "",
"created_at": "2021-09-30T21:24:05.000Z",
"updated_at": "2021-09-30T17:53:29.000Z"
}
]
var maxDateIndex = 0;
var newData = data.map((item, index) => {
if(item.updated_at > data[maxDateIndex].updated_at)
maxDateIndex = index;
item.is_latest = "false";
return item;
});
newData[maxDateIndex].is_latest = "true";
console.log(newData);No need to convert to Date objects and back; stick with strings and use localeCompare. Then just reverse sort the values and choose the first one.
let data = [{
"is_latest": "",
"created_at": "2021-09-21T21:24:05.000Z",
"updated_at": "2021-09-21T17:53:29.000Z"
},
{
"is_latest": "",
"created_at": "2021-09-22T21:24:05.000Z",
"updated_at": "2021-09-22T17:53:29.000Z"
},
{
"is_latest": "",
"created_at": "2021-09-29T21:24:05.000Z",
"updated_at": "2021-09-29T17:53:29.000Z" // this is the latest data
}
];
const trueVal = true; // change to "true" if you want a string
const falseVal = false; // change to "false" if you want a string
data.sort((a, b) => b.updated_at.localeCompare(a.updated_at));
data[0].is_latest = trueVal;
data.filter(datum => !datum.is_latest).forEach(datum => datum.is_latest = falseVal);
console.log(data);