2024 JavaScript core features prospect

This article will explore in-depth the highly anticipated new JavaScript features in 2024, which are most likely to be included in this year's ECMAScript version: Temporal, pipeline operators, records and tuples, regular expressions/v flags, and decorators .

ECMAScript update

A new JS version has been released every year since the ES6 update, and this year's ES2024 version is expected to be released around June. ES6 is a huge version update, six years after its predecessor ES5. Browser manufacturers and JavaScript developers are all overwhelmed by a large number of feature updates. To avoid this happening again, a new version will be released every year thereafter.

Releasing new versions every year involves proposals, discussions, evaluations and committee votes on new features. This process also allows the browser to try to implement features before they are officially added to the language, which helps solve any implementation issues. As mentioned earlier, the new features of JavaScript (or ECMAScript) are decided by the Technical Committee 39 (TC39). TC39 is composed of representatives from all major browser manufacturers and JavaScript experts. They meet regularly to discuss new features of language and how to implement them. New features are presented in the form of proposals, and then committee members vote to decide whether each proposal can move to the next stage. Each proposal has 4 stages; once the proposal reaches stage 4, it is expected to be included in the next ES version. An important part of the ES specification is that it must be backward compatible. This means that no new feature can "break the Internet" by changing the way previous ES versions run. Therefore, they cannot change the way existing methods work, they can only add new methods, because any website that uses potentially pre-existing methods can be at risk of crash. A complete list of all current proposals can be viewed here.

Temporal

In the 2022 JS Status Survey, the third most common answer to "What do you think JavaScript is most lacking at the moment?" is better date management. This led to the advent of the Temporal proposal, which provides a standard global object to replace the Date object and fixes many issues that JavaScript developers have encountered in dealing with dates over the years. Handling dates in JavaScript is almost always a headache; having to deal with subtle but annoying differences, such as months are zero-indexed, but the number of days in the month starts at 1. Date difficulties have led to the emergence of popular libraries such as Moment, Day.JS, and date-fns, trying to solve these problems. However, the Temporal API is designed to fix all issues natively. Temporal will support multiple time zones and non-Gregorian calendars out of the box and will provide an easy-to-use API to make parsing dates from strings easier. Additionally, all Temporal objects will be immutable, which will help avoid any unexpected date change errors. Let's look at some of the most useful methods provided by the Temporal API.

• Temporal.Now.Instant(): Returns a DateTime object that is accurate to nanoseconds. You can use the from method to specify a specific date.

• PlainDate(): Allows you to create a date object with only dates and no time.

• PlainTime(): Complemented with PlainDate(), it allows you to create a time object with only time and no date.

• PlainMonthDay(): Similar to PlainDate, but it only returns month and date, no year information.

• PlainYearMonth(): Similarly, there is PlainYearMonth, which returns only the year and month.

• Computation: Many calculations can be performed using Temporal objects, such as adding and subtracting various time units. The until and since methods allow you to find out how much time has been until a date or since it has occurred.

• Other features: You can extract years, months, and dates from Date objects, as well as hours, minutes, seconds, milliseconds, microseconds, and nanoseconds from Time objects. The Temporal date object will also have a compare method that can be used to sort dates using various sorting algorithms.

Temporal is currently a Phase 3 proposal that is being implemented by browser manufacturers, so it looks like its time is ripe. You can view the full documentation here. There is also a useful use case recipe here. When combined with the Intl.DateTimeFormat API, you will be able to do some very clever date operations.

Pipe operator

In the 2022 JS Status Survey, the sixth most common answer to "What do you think JavaScript is most lacking at the moment?" is the pipeline operator. You can view the pipeline operator proposal here. Pipe operators are a standard feature in functional languages ??that allow you to "pipe" values ??from one function to another, with the output of the previous function being used as input to the next function.

The pipeline operator combines the ease of chain calls, but can be used with any function you write. The only condition is that you need to make sure that the output type of one function matches the input type of the next function in the chain. Pipeline operators are best suited for Curry functions that accept only a single parameter, which is passed from the return value of any previous function. It makes functional programming easier because small, building block functions can be linked together to create more complex composite functions. It also makes some applications easier to implement.

Records and Tuples

Record and tuple proposals are designed to introduce immutable data structures into JavaScript. Tuples are similar to arrays—sorted lists of values—but they are immutable in depth. This means that each value in the tuple must be the original value, another record, or tuple (not an array or object, because they are mutable in JavaScript). Records are similar to a collection of objects—key-value pairs—but they are also immutable in depth.

tuples and records means you can easily compare them using the === operator.

regular expression /v flag

Regular expressions have been incorporated into JavaScript since version 3, and many improvements have been made since then (e.g. Unicode support using the u flag in ES2015). The v-flag proposal is designed to do all the operations performed by the u-flag, but it also adds some additional advantages. The /v flag also solves some of the problems with the u flag in case insensitive, making it a better choice in almost all cases. The /v flag for regular expressions reached Phase 4 in 2023 and has been implemented in all major browsers, so it is expected to be part of the ES2024 specification.

Decorators

The decorator proposal is intended to use decorators to natively extend JavaScript classes. Decorators are already common in many object-oriented languages ??such as Python and are already included in TypeScript. They are a standard metaprogramming abstraction that allows you to add extra functionality to a function or class without changing its structure. This proposal adds some syntax sugar, allowing you to easily implement decorators in your class without considering binding this to the class. It provides a clearer way to extend class elements such as class fields, class methods, or class accessors, which can even be applied to the entire class.

Conclusion

All of these features will be a major addition to JavaScript, so let's wait and see if they can be included this year!

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