Versions
In June 2004, Ecma International published ECMA-357 standard, defining an extension to ECMAScript, known as ECMAScript for XML (E4X). Ecma also defined a "Compact Profile" for ECMAScript – known as ES-CP, or ECMA 327 – that was designed for resource-constrained devices, which was withdrawn in 2015.2015-03-24 Meeting Notes4th Edition (abandoned)
The proposed fourth edition of ECMA-262 (ECMAScript 4 or ES4) would have been the first major update to ECMAScript since the third edition was published in 1999. The specification (along with a reference implementation) was originally targeted for completion by October 2008. The first draft was dated February 1999. An overview of the language was released by the working group on 23 October 2007. By August 2008, the ECMAScript 4th edition proposal had been scaled back into a project code named ECMAScript Harmony. Features under discussion for Harmony at the time included: * classes, * a module system, * optional type annotations and static typing, probably using a structural type system, * generators and iterators, * destructuring assignment, and * algebraic data types. The intent of these features was partly to better support '' programming in the large'', and to allow sacrificing some of the script's ability to be dynamic to improve performance. For example, Tamarin – the virtual machine for ActionScript, developed and open-sourced by Adobe – has just-in-time compilation (JIT) support for certain classes of scripts. In addition to introducing new features, some ES3 bugs were proposed to be fixed in edition 4. These fixes and others, and support for5th Edition – ECMAScript 2009
Yahoo, Microsoft, Google, and other 4th edition dissenters formed their own subcommittee to design a less ambitious update of ECMAScript 3, tentatively named ECMAScript 3.1. This edition would focus on security and library updates, with a large emphasis on compatibility. After the aforementioned public sparring, the ECMAScript 3.1 and ECMAScript 4 teams agreed on a compromise: the two editions would be worked on, in parallel, with coordination between the teams to ensure that ECMAScript 3.1 remains a strict subset of ECMAScript 4 in both semantics and syntax. However, the differing philosophies in each team resulted in repeated breakages of the subset rule, and it remained doubtful that the ECMAScript 4 dissenters would ever support or implement ECMAScript 4 in the future. After over a year since the disagreement over the future of ECMAScript within the Ecma Technical Committee 39, the two teams reached a new compromise in July 2008:String.trim() to easily remove whitespaces surrounding a string (" example " to "example"), String.charAt() to return a single character from a given position in a string, and Array.isArray(). A comma after the final pair of values in an object (var example = ) also no longer causes a syntax error.
6th Edition – ECMAScript 2015
The 6th edition, ECMAScript 6 (ES6) and later renamed to ECMAScript 2015, was finalized in June 2015. This update adds significant new syntax for writing complex applications, including class declarations (let keyword for local declarations, const keyword for constant local declarations, binary data, typed arrays, new collections (maps, sets and WeakMap), promises, number and math enhancements, reflection, proxies (metaprogramming for virtual objects and wrappers) and template literals using backticks (`) for multi-line strings without escape characters. The complete list is extensive. As the first "ECMAScript Harmony" specification, it is also known as "ES6 Harmony".
7th Edition – ECMAScript 2016
The 7th edition, or ECMAScript 2016, was finalized in June 2016. Its features include exponentiation operator** for numbers, await, async keywords for asynchronous programming (as a preparation for ES2017), and the function. The exponentiation operator is equivalent to , but provides a simpler syntax similar to languages like Python, F#, Perl, and Ruby. async / await was hailed as an easier way to use promises and develop asynchronous code.
8th Edition – ECMAScript 2017
The 8th edition, or ECMAScript 2017, was finalized in June 2017. Its features include the , and functions for easy manipulation of Objects,async / await constructions that use generators and promises, and additional features for concurrency and atomics. It also includes String.prototype.padStart().
9th Edition – ECMAScript 2018
The 9th edition, or ECMAScript 2018, was finalized in June 2018. New features include the spread operator and rest parameters (...) for object literals, asynchronous iteration, Promise.prototype.finally and additions to RegExp.
The spread operator allows for the easy copying of object properties, as shown below.10th Edition – ECMAScript 2019
The 10th edition, or ECMAScript 2019, was published in June 2019. Added features include, but are not limited to,Array.prototype.flat, Array.prototype.flatMap, changes to Array.sort, and Object.fromEntries.
is now guaranteed to be stable, meaning that elements with equal sorting keys will not change relative order before and after the sort operation. Array.prototype.flat(depth=1) flattens an array to a specified depth, meaning that all subarray elements (up to the specified depth) are concatenated recursively.
Another notable change is that so-called ''catch binding'' became optional.
11th Edition – ECMAScript 2020
The 11th edition, or ECMAScript 2020, was published in June 2020. In addition to new functions, this version introduces aBigInt primitive type for arbitrary-sized integers, the nullish coalescing operator, and the globalThis object.
BigInts are created either with the constructor or with the syntax , where "n" is placed after the number literal. BigInts allow the representation and manipulation of integers beyond , while Numbers are represented by a double-precision 64-bit 12th Edition – ECMAScript 2021
The 12th edition, ECMAScript 2021, was published in June 2021. This version introduces the method for strings; , a promise combinator that short-circuits when an input value is fulfilled; , a new error type to represent multiple errors at once; logical assignment operators (, ,, , =); , for referring to a target object without preserving it from garbage collection, and , to manage registration and unregistration of cleanup operations performed when target objects are garbage collected; separators for numeric literals (); and was made more precise, reducing the number of cases that result in an implementation-defined sort order.
13th Edition – ECMAScript 2022
The 13th edition, ECMAScript 2022, was published in June 2022. This version introduces top-level , allowing the keyword to be used at the top level of modules; new class elements: public and private instance fields, public and private static fields, private instance methods and accessors, and private static methods and accessors; static blocks inside classes, to perform per-class evaluation initialization; the syntax, to test for presence of private fields on objects;14th Edition – ECMAScript 2023
The 14th edition, ECMAScript 2023, was published in June 2023. This version introduces thetoSorted, toReversed, with, findLast, and findLastIndex methods on Array.prototype and TypedArray.prototype, as well as the toSpliced method on Array.prototype; added support for #! shebang comments at the beginning of files to better facilitate executable ECMAScript files; and allowed the use of most Symbols as keys in weak collections.
15th Edition – ECMAScript 2024
The 15th edition, ECMAScript 2024, was published in June 2024. This version introduces theObject.groupBy and Map.groupBy static methods, Promise.withResolvers, various set operations on Set.prototype, and the /v unicode flag for regular expressions.
The Object.groupBy and Map.groupBy methods group an iterable collection using the return value of a provided callback function.Promise.withResolvers provides a simple way to get a promise's resolve and reject functions directly without having to assign them in the constructor./v flag in regular expressions is simply an improved version of the /u flag, but as it makes backwards-incompatible changes it had to be introduced as a new flag.
ES.Next
ES.Next is a dynamic name that refers to whatever the next version is at the time of writing. ES.Next features include finished proposals (aka "stage 4 proposals") as listed aReferences
External links
JavaScript 1.0
* As implemented in Netscape Navigator 2.0 before submitting the first version for standardization as Ecmascript: {{cite web , url=http://home.netscape.com/eng/mozilla/2.0/handbook/javascript/index.html , title=JavaScript Authoring Guide , access-date=2023-10-13 , archive-date=1997-06-13 , archive-url=https://web.archive.org/web/19970613234917/http://home.netscape.com/eng/mozilla/2.0/handbook/javascript/index.html , url-status=bot: unknownISO standards
ECMA standards