Consider the following array of objects:
const data = [
*{...more data from previous dates}*,
{
unixDate: 1650348034, //yesterday
dateTime: Tue Apr 19 2022 23:00:34,
severityLevel: 1,
severity: "Light"
},
{
unixDate: 1650348034, //yesterday
dateTime: Tue Apr 19 2022 14:00:34,
severityLevel: 3,
severity: "Moderate"
},
{
unixDate: 1650440700, //today
dateTime: Wed Apr 20 2022 15:45:00,
severityLevel: 2,
severity: "Moderate-Light"
},
{
unixDate: 1650442500, //today
dateTime: Wed Apr 20 2022 15:45:00,
severityLevel: 4,
severity: "Heavy"
},
{
unixDate: 1650427234, //today
dateTime: Wed Apr 20 2022 12:00:00,
severityLevel: 3,
severity: "Moderate"
}
]
I would like to return the following:
{
*///...records from previous dates,*
1650348034 : 2, //yesterday record taking only one of the unixtimestamp, and the average value of 'severityLevel'.
1650440700 : 3 //same as above but unixtimestamp is today.
}
I'm using the dayjs package to determine whether or not the date is today, via the isToday plugin, but couldn't think of how to compare the dates. The data is growing everyday as it records new readings. I'm not too familiar with the array filter/reduce methods in ES6, would they be useful here? Any help is appreciated!
Another approach with an util method dayBegins which will calculate the day begin time stamp. This will be useful identify whether timestamps fall into same day or not.
Along with that, just build an tracking object with keys as dayBegin and values with severityLevel and number occurences.
const dayBegins = (uDate) =>
"" + uDate * 1000 - ((uDate * 1000) % (24 * 60 * 60 * 1000));
const process = (arr, output = {}) => {
arr.forEach(({ unixDate, severityLevel }) => {
const key = dayBegins(unixDate);
if (key in output) {
output[key].count += 1;
output[key].sum += severityLevel;
} else {
output[key] = {
unixDate,
count: 1,
sum: severityLevel,
};
}
});
return Object.values(output).reduce(
(acc, { unixDate, sum, count }) =>
Object.assign(acc, { [unixDate]: sum / count }),
{}
);
};
const data = [
{
unixDate: 1650348034, //yesterday
dateTime: "Tue Apr 19 2022 23:00:34",
severityLevel: 1,
severity: "Light",
},
{
unixDate: 1650348034, //yesterday
dateTime: "Tue Apr 19 2022 14:00:34",
severityLevel: 3,
severity: "Moderate",
},
{
unixDate: 1650440700, //today
dateTime: "Wed Apr 20 2022 15:45:00",
severityLevel: 2,
severity: "Moderate-Light",
},
{
unixDate: 1650442500, //today
dateTime: "Wed Apr 20 2022 15:45:00",
severityLevel: 4,
severity: "Heavy",
},
{
unixDate: 1650427234, //today
dateTime: "Wed Apr 20 2022 12:00:00",
severityLevel: 3,
severity: "Moderate",
},
];
console.log(process(data))First you need to convert those unix times to javascript Date objects. Then you can group by the year/month/date and then average the results.
const data = [
{
unixDate: 1650348034, //yesterday
dateTime: "Tue Apr 19 2022 23:00:34",
severityLevel: 1,
severity: "Light"
},
{
unixDate: 1650348034, //yesterday
dateTime: "Tue Apr 19 2022 14:00:34",
severityLevel: 3,
severity: "Moderate"
},
{
unixDate: 1650440700, //today
dateTime: "Wed Apr 20 2022 15:45:00",
severityLevel: 2,
severity: "Moderate-Light"
},
{
unixDate: 1650442500, //today
dateTime: "Wed Apr 20 2022 15:45:00",
severityLevel: 4,
severity: "Heavy"
},
{
unixDate: 1650427234, //today
dateTime: "Wed Apr 20 2022 12:00:00",
severityLevel: 3,
severity: "Moderate"
}
]
const x = Object.values(data.map(x => ({...x, dateTime: new Date(x.unixDate * 1000)}))
.reduce( (acc,i) => {
const key = "" + i.dateTime.getFullYear() + i.dateTime.getMonth() + i.dateTime.getDate();
acc[key] = acc[key] || [];
acc[key].push(i);
return acc
},{}))
.reduce( (obj,rec) => {
return {...obj, [rec[0].unixDate]: rec.reduce( (acc,i) => acc+i.severityLevel,0) / rec.length }
},{})
console.log(x)Nothe that if the property dateTime is already a javascript date you can do without the data.map(x => ({...x, dateTime: new Date(x.unixDate * 1000)})) part.
Gets a unique list of days and builds an object based on the calculated days
const data = [ { unixDate: 1650348034, dateTime: "Tue Apr 19 2022 23:00:34", severityLevel: 1, severity: "Light" }, { unixDate: 1650348034, dateTime: "Tue Apr 19 2022 14:00:34", severityLevel: 3, severity: "Moderate" }, { unixDate: 1650440700, dateTime: "Wed Apr 20 2022 15:45:00", severityLevel: 2, severity: "Moderate-Light" }, { unixDate: 1650442500, dateTime: "Wed Apr 20 2022 15:45:00", severityLevel: 4, severity: "Heavy" }, { unixDate: 1650427234, dateTime: "Wed Apr 20 2022 12:00:00", severityLevel: 3, severity: "Moderate" } ]
//Get unique list of days
let unique = [... new Set(data.map(d => new Date(d.unixDate * 1000).toLocaleDateString("en-US")))];
//build object based on this list
let results = Object.fromEntries(unique.map(m => {
let records = data.filter(v => new Date(v.unixDate * 1000).toLocaleDateString("en-US") === m);
return [records[0].unixDate, records.reduce((v,o) => v+=o.severityLevel, 0) / records.length ]
}));
console.log(results);