Day.js | The lightest API to handle dates in JS

Today I am writing again to bring you a library that will help us with the handling of dates in JavaScript, yes, as we all know the handling of dates in JavaScript is not very intuitive.

🤔 Why use dayjs?

Basically the justification for using dayjs is to simplify the handling of dates in JavaScript.

It is a fairly widespread library and which you have probably heard of already, it was presented a while ago as an alternative to Moment which is not recommended for use today, the main reason is the weight and the appearance of new alternatives that offer more modern and lighter solutions, dayjs is an example of this.

Moment

see more here

Dayjs

see more here

It is very light because it takes advantage of the Treeshaking since the library is fully extensible through plugins that we will add depending on the needs that arise, in this way we will only import the things we need.

🧪 Some examples

Now we will go to see some examples where its use would be justified compared to the native API, either for simplicity, readability or also to prevent possible errors.

We are going to review some of the most interesting functionalities that dayjs offers us.

🧹 Without plugins

Get difference in days between two dates

docs

import dayjs from "dayjs";

dayjs(new Date(2020, 5, 10)).diff(new Date(2020, 5, 1), "day"); // output:  9

Check if the given date is valid or not

docs

import dayjs from "dayjs";

dayjs("20").isValid(); // output:  false
dayjs("2021-09-13").isValid(); // output:  true

Get the number of days in the month

docs

import dayjs from "dayjs";

dayjs("2021-09-13").daysInMonth() // output: 30

Add days, months, years, hours, minutes, seconds etc.

docs

import dayjs from "dayjs";

dayjs("2021-09-13 20:09:09").add(20, "minute").format() // output: 2021-09-13T20:29:09+02:00

Subtract days, months, years, hours, minutes, seconds etc

docs

import dayjs from "dayjs";

dayjs("2021-09-13 20:09:09").subtract(20, "minute").format() // output: 2021-09-13T19:49:09+02:00

⚡ Extending the functionality through plugins

RelativeTime

docs

Get time difference in string format between current date and given date using Spanish locale

import dayjs from "dayjs";
import relativeTime from "dayjs/plugin/relativeTime";
import "dayjs/locale/es";

dayjs.locale("es");
dayjs.extend(relativeTime);

dayjs("2021-09-14T13:28:55.979Z").fromNow(); // example output: en 3 horas

WeekOfYear

docs

Get week of year

import dayjs from "dayjs";
import weekOfYear from "dayjs/plugin/weekOfYear";

dayjs.extend(weekOfYear);

dayjs("2021-09-13T13:28:55.979Z").week(); // output: 38

IsSameOrAfter

docs

Check if one date is equal to or greater than another

import dayjs from "dayjs";
import isSameOrAfter from "dayjs/plugin/isSameOrAfter";

dayjs.extend(isSameOrAfter);

// To use `year` granularity pass the second parameter
dayjs("2021-09-13").isSameOrAfter("2021-09-14", "year"); // output: true

MinMax

docs

Get the highest date or the lowest date among the dates of an array

import dayjs from "dayjs";
import minMax from "dayjs/plugin/minMax";

dayjs.extend(minMax)

const maxDate = dayjs.max([
    dayjs("2021-09-13"), 
    dayjs("2021-09-16"), 
    dayjs("2021-09-20")
])

const minDate = dayjs.min([
    dayjs("2021-09-13"), 
    dayjs("2021-09-16"), 
    dayjs("2021-09-20")
])

maxDate.format() // output: 2021-09-20T00:00:00+02:00  
minDate.format() // output: 2021-09-13T00:00:00+02:00

IsBetween

docs

Check if the given date is within the indicated date range

import dayjs from "dayjs";
import isBetween from "dayjs/plugin/isBetween";

dayjs.extend(isBetween);

// To use `day` granularity pass the third parameter
dayjs("2010-10-21").isBetween(dayjs("2010-10-20"), dayjs("2010-10-25"), "day"); //output: true

// To use `year` granularity pass the third parameter
dayjs("2010-10-21").isBetween(dayjs("2010-10-20"), dayjs("2010-10-25"), "year"); //output: false

AdvancedFormat

docs

Vitamin default formatting options

import dayjs from "dayjs";
import advancedFormat from "dayjs/plugin/advancedFormat";

dayjs.extend(advancedFormat);

dayjs("2021-09-14").format("Q Do k kk X x"); // output: 3 14th 24 24 1631570400 1631570400000

As can be seen in the examples above, the API is quite simple and readable, it seems to me without a doubt a great option if we need to solve some other complex function with dates in JavaScript.

For view more information go to official dayjs docs.

Thanks for reading me. 😊