ECMAScript6标准-简介

Introduction

This Ecma Standard defines the ECMAScript 2015 Language. It is the sixth edition of the ECMAScript Language Specification. Since publication of the first edition in 1997, ECMAScript has grown to be one of the world’s most widely used general purpose programming languages. It is best known as the language embedded in web browsers but has also been widely adopted for server and embedded applications.The sixth edition is the most extensive update to ECMAScript since the publication of the first edition in 1997.

前言

该Ecma标准定义了ECMAScript 2015语言。 这是ECMAScript语言规范的第六版。 自1997年发行第一版以来，ECMAScript已发展成为世界上使用最广泛的通用编程语言之一。 它是总所周知的嵌入网络浏览器的语言，但也被服务器和嵌入式应用程序广泛采用。第六版是自1997年第一版发布以来对ECMAScript的最广泛的更新。

Goals for ECMAScript 2015 include providing better support for large applications, library creation, and for use of ECMAScript as a compilation target for other languages. Some of its major enhancements include modules, class declarations, lexical block scoping, iterators and generators, promises for asynchronous programming, destructuring patterns, and proper tail calls. The ECMAScript library of built-ins has been expanded to support additional data abstractions including maps, sets, and arrays of binary numeric values as well as additional support for Unicode supplemental characters in strings and regular expressions. The built-insarenow extensible via subclassing.

ECMAScript 2015的目标包括为大型应用程序，库创建以及将ECMAScript用作其他语言的编译目标提供更好的支持。 它的一些主要增强功能包括模块，类声明，词汇块作用域，迭代器和生成器，对异步编程的承诺，解构模式以及适当的尾部调用。 扩展了内置的ECMAScript库，以支持附加的数据抽象，包括映射，集合和二进制数值数组，以及对字符串和正则表达式中Unicode补充字符的额外支持。 内置组件现在可以通过子类扩展。

ECMAScript is based on several originating technologies, the most well-known beingJavaScript (Netscape) and JScript (Microsoft). The language was invented by Brendan Eich at Netscape and first appeared in that company’s Navigator 2.0 browser. It has appeared in all subsequent browsers from Netscape and in all browsers from Microsoft starting with Internet Explorer 3.0.

ECMAScript基于多种原始技术，最著名的是JavaScript(网景[公司名])和JScript(微软)。 该语言是网景的Brendan Eich发明的，最早出现在该公司的Navigator 2.0浏览器中。 从Internet Explorer 3.0开始，它出现在网景的所有后续浏览器以及微软的所有浏览器中。

The development of the ECMAScript Language Specification started in November 1996. The first edition of this Ecma Standard was adopted by the Ecma General Assembly of June 1997.

ECMAScript语言规范的开发始于1996年11月。Ecma标准的第一版于1997年6月由Ecma大会采用。

That Ecma Standard was submitted to ISO/IECJTC 1 for adoption under the fast-track procedure, and approved as international standard ISO/IEC 16262, in April 1998. The Ecma General Assembly of June 1998 approved the second edition of ECMA-262 to keep it fully aligned with ISO/IEC 16262. Changes between the first and the second edition are editorial in nature.

那个Ecma标准已按照快速程序提交给ISO / IECJTC 1并通过，并于1998年4月被批准为国际标准ISO / IEC16262。1998年6月的Ecma大会批准了ECMA-262的第二版，以保持它完全符合ISO / IEC16262。第一版和第二版之间的改变本质上是社论。

The third edition of the Standard introduced powerful regular expressions, better string handling, new control statements, try/catch exception handling, tighter definition of errors, formatting for numeric output and minor changes in anticipation future language growth. The third edition of the ECMAScript standard was adopted by the Ecma General Assembly of December 1999 and published as ISO/IEC 16262:2002 in June 2002.

该标准的第三版引入了强大的正则表达式，更好的字符串处理，新的控制语句，try / catch异常处理，更严格的错误定义，数字输出格式以及对预期未来语言成长的细微更改。 ECMAScript标准的第三版于1999年12月由Ecma大会采用，并于2002年6月作为ISO / IEC 16262：2002发布。

After publication of the third edition, ECMAScript achieved massive adoption in conjunction with the World Wide Web where it has become the programming language that is supported by essentially all web browsers. Significant work was done to develop a fourth edition of ECMAScript. However,that work was not completed and not published1as the fourth edition of ECMAScriptbut some of it was incorporated into the development of the sixth edition.

在发布第三版之后，ECMAScript与万维网一起获得了广泛的采用，万维网已经成为基本上所有Web浏览器都支持的编程语言。 开发ECMAScript第四版的工作量很大。 但是，该工作尚未完成，也没有作为ECMAScript的第四版发布，但是其中一些已并入第六版的开发中。

The fifth edition of ECMAScript (published as ECMA-262 5thedition) codifiedde facto interpretations of the language specification that have become common among browser implementations and addedsupport for new features that hademerged since the publication of the third edition. Such features include accessor properties, reflective creation and inspection of objects, program control of property attributes, additional array manipulation functions, support for the JSON object encoding format, and a strict mode that provides enhanced error checking and program security.The Fifth Edition was adopted by the Ecma General Assembly of December 2009.

ECMAScript的第五版(作为ECMA-262第5版发行)对语言规范的事实解释进行了编纂，这些解释在浏览器实现中已变得常见，并增加了对自第三版发布以来已经出现的新功能的支持。 这些功能包括访问器属性，对象的反射式创建和检查，属性特性的程序控制，附加的数组操作功能，对JSON对象编码格式的支持以及提供增强的错误检查和程序安全性的严格模式。第五版于2009年12月由Ecma大会通过。

Note: Please note that for ECMAScript Edition 4 the Ecma standard number “ECMA-262 Edition 4” was reserved but not used in the Ecma publication process. Therefore “ECMA-262 Edition 4” as an Ecma International publication does not exist.

注意：请注意，对于ECMAScript版本4，Ecma标准号“Ecma-262版本4”是保留的，但在Ecma发布过程中未使用。因此，“ECMA-262版4”作为ECMA国际出版物不存在。

The fifth Edition was submitted to ISO/IEC JTC 1 for adoption under the fast-track procedure, and approved asinternational standard ISO/IEC 16262:2011.Edition 5.1 of the ECMAScript Standard incorporated minor corrections and is the same text as ISO/IEC 16262:2011. The 5.1Edition was adopted by the Ecma General Assembly of June 2011.

第五版已提交给ISO / IEC JTC 1以在快速程序下通过，并被批准为国际标准ISO / IEC 16262：2011。ECMAScript标准的5.1版包含一些较小的更正，并且与ISO / IEC 16262：2011 文本相同。 5.1版于2011年6月由Ecma大会通过。

Focused development of the sixth edition started in 2009, as the fifth edition was being prepared for publication. However, this was preceded by significant experimentation and language enhancement design efforts dating to the publication of the third edition in 1999. In a very real sense, the completion of the sixth edition is the culmination of a fifteen year effort.

第六版的重点开发工作始于2009年，当时正准备出版第五版。 但是，此之前要进行大量的实验和语言增强设计工作，直到1999年第三版出版为止。实际上，第六版的完成是十五年努力的结晶。

Dozens of individuals representing many organizations have made very significant contributions within Ecma TC39 to the development of this edition and to the prior editions. In addition, a vibrant informal community has emerged supporting TC39’s ECMAScript efforts. This community has reviewed numerous drafts, filed thousands of bug reports, performed implementation experiments, contributed test suites, and educated the world-wide developer community about ECMAScript. Unfortunately, it is impossible to identify and acknowledge every person and organization who has contributed to this effort.

在Ecma TC39中，数十个代表许多组织的个人为该版本和以前版本的开发做出了非常重要的贡献。 此外，已经出现了一个充满活力的非正式社区，以支持TC39的ECMAScript工作。 该社区审查了许多草案，提交了成千上万的bug报告，执行了实施实验，提供了测试套件，并对全球开发人员社区进行了ECMAScript教育。 不幸的是，不可能确定和答谢为这一努力做出贡献的每个人和组织。

New uses and requirements for ECMAScript continue to emerge. The sixth edition provides the foundation for regular, incremental language and library enhancements.

Allen Wirfs-Brock

ECMA-262, 6th Edition Project Editor

This Ecma Standard has been adopted by the General Assembly of June2015.

ECMAScript的新用途和要求不断涌现。 第六版为常规，增量语言和库增强功能提供了基础。

艾伦 维尔夫斯·布洛克

ECMA-262，第六版项目编辑

此Ecma标准已于2015年6月由大会通过。