Top Related Projects
HTML Standard
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
Node.js JavaScript runtime ✨🐢🚀✨
🐠 Babel is a compiler for writing next generation JavaScript.
Find and fix problems in your JavaScript code.
Prettier is an opinionated code formatter.
Quick Overview
The tc39/ecma262 repository is the official home of the ECMAScript specification, which defines the JavaScript programming language. This repository contains the source for ECMA-262, the ECMAScript Language Specification, and is maintained by the TC39 committee responsible for evolving the ECMAScript programming language.
Pros
- Provides a centralized, authoritative source for the latest ECMAScript specification
- Allows for community involvement through issues and pull requests
- Offers transparency in the language evolution process
- Includes detailed explanations and rationales for language features
Cons
- Can be complex and technical for non-experts to understand
- The specification language may be difficult for casual JavaScript developers to interpret
- Updates to the specification can take a long time due to the rigorous review process
- Implementing new features across all JavaScript engines can be challenging and time-consuming
Code Examples
As this is not a code library but a specification repository, code examples are not applicable. The repository contains the formal specification for the JavaScript language rather than executable code.
Getting Started
Since this is not a code library, there are no specific getting started instructions. However, for those interested in following the development of the ECMAScript specification:
- Visit the tc39/ecma262 repository on GitHub.
- Read the README.md file for an overview of the project.
- Explore the spec.html file for the latest editor's draft of the ECMAScript specification.
- Check the proposals repository to see upcoming features and their stages in the TC39 process.
- Join the discussions in the issues section to participate in the language evolution process.
Competitor Comparisons
HTML Standard
Pros of HTML
- More comprehensive documentation and explanations
- Broader scope, covering entire web platform
- Active community with frequent updates and discussions
Cons of HTML
- Larger and more complex specification
- Slower standardization process due to broader scope
- Less focused on specific language features
Code Comparison
HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
ECMA262:
const obj = {
prop: 'value',
method() {
return this.prop;
}
};
The HTML repository focuses on defining the structure and semantics of web documents, while ECMA262 specifies the core JavaScript language. HTML provides a more comprehensive view of web technologies, including DOM, CSSOM, and other APIs. ECMA262, on the other hand, concentrates on JavaScript syntax, semantics, and core functionality.
Both repositories are crucial for web development, with HTML offering a broader perspective on web standards and ECMA262 providing in-depth specifications for JavaScript language features. Developers often need to refer to both specifications when working on web applications, as they complement each other in defining the modern web platform.
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
Pros of TypeScript
- Adds static typing to JavaScript, enhancing code quality and developer productivity
- Provides advanced tooling support, including better autocomplete and refactoring capabilities
- Compiles to standard JavaScript, allowing seamless integration with existing projects
Cons of TypeScript
- Requires a compilation step, which can add complexity to the development process
- May have a steeper learning curve for developers new to static typing
- Not all JavaScript libraries have TypeScript type definitions, potentially limiting compatibility
Code Comparison
ECMA262 (JavaScript):
function greet(name) {
return `Hello, ${name}!`;
}
console.log(greet("World"));
TypeScript:
function greet(name: string): string {
return `Hello, ${name}!`;
}
console.log(greet("World"));
The TypeScript example adds type annotations to the function parameter and return value, providing additional type safety and improved tooling support.
Node.js JavaScript runtime ✨🐢🚀✨
Pros of Node.js
- More active community with frequent updates and contributions
- Broader scope, covering server-side JavaScript runtime and ecosystem
- Extensive package ecosystem through npm
Cons of Node.js
- Less focused on language specification, more on implementation
- May introduce non-standard features or behaviors
- Faster-moving, potentially less stable than ECMA-262
Code Comparison
ECMA-262 (JavaScript specification):
// Example of optional chaining operator
const value = object?.property?.nestedProperty;
Node.js (runtime implementation):
// Example of Node.js-specific API
const fs = require('fs');
fs.readFile('file.txt', 'utf8', (err, data) => {
if (err) throw err;
console.log(data);
});
ECMA-262 focuses on defining language features and syntax, while Node.js implements these features and provides additional APIs for server-side development. The ECMA-262 example shows a language feature, while the Node.js example demonstrates platform-specific functionality.
🐠 Babel is a compiler for writing next generation JavaScript.
Pros of Babel
- Practical implementation of ECMAScript features, allowing developers to use new syntax immediately
- Extensive plugin ecosystem for customizing JavaScript transformations
- Actively maintained with frequent updates and community support
Cons of Babel
- Adds complexity to the build process and potential performance overhead
- May introduce subtle differences from native implementations
- Requires ongoing maintenance to keep up with evolving ECMAScript standards
Code Comparison
ECMA262 (specification):
// Example of optional chaining syntax
let nestedProp = obj?.prop?.nestedProp;
Babel (transpiled output):
var _obj, _obj$prop;
let nestedProp = (_obj = obj) === null || _obj === void 0 ? void 0 : (_obj$prop = _obj.prop) === null || _obj$prop === void 0 ? void 0 : _obj$prop.nestedProp;
Summary
ECMA262 is the official specification for ECMAScript, defining language features and behavior. Babel is a popular transpiler that implements these features, allowing developers to use modern JavaScript syntax in environments that don't natively support it. While ECMA262 provides the standard, Babel offers practical tools for developers to adopt new language features quickly, at the cost of some additional complexity in the development process.
Find and fix problems in your JavaScript code.
Pros of ESLint
- More practical and immediately applicable for developers
- Highly customizable with a wide range of plugins and configurations
- Actively maintained with frequent updates and bug fixes
Cons of ESLint
- Narrower scope, focused solely on linting JavaScript code
- Less influence on the evolution of the JavaScript language itself
Code Comparison
ESLint configuration example:
{
"rules": {
"semi": ["error", "always"],
"quotes": ["error", "double"]
}
}
ECMA-262 specification example:
function* generator() {
yield 1;
yield 2;
yield 3;
}
Additional Notes
ECMA262 is the official specification for the ECMAScript language, which forms the foundation of JavaScript. It defines the core language features and syntax, while ESLint is a tool built on top of the language to enforce coding standards and best practices.
ESLint is more directly useful for day-to-day development tasks, helping developers catch errors and maintain consistent code style. ECMA262, on the other hand, is crucial for language implementers and those interested in the evolution of JavaScript itself.
While both projects are open-source and accept contributions, the process for contributing to ECMA262 is more formal and involves a committee review process, reflecting its role as the official language specification.
Prettier is an opinionated code formatter.
Pros of Prettier
- More focused and practical tool for immediate use in development
- Larger community with frequent updates and active maintenance
- Easier for developers to contribute and influence the project
Cons of Prettier
- Limited scope compared to the comprehensive language specification
- May not always align perfectly with evolving ECMAScript standards
- Less authoritative in terms of language definition and standardization
Code Comparison
ECMA262 (language specification):
function example(x) {
if (x) {
return x;
} else {
return !x;
}
}
Prettier (formatted code):
function example(x) {
if (x) {
return x;
} else {
return !x;
}
}
While ECMA262 defines the language syntax, Prettier enforces consistent formatting. In this case, both representations are valid, but Prettier ensures consistent spacing and indentation across a project.
ECMA262 is the official specification for ECMAScript (JavaScript), providing a comprehensive definition of the language. It serves as the authoritative reference for implementers and advanced developers.
Prettier, on the other hand, is a practical code formatting tool used in day-to-day development. It automatically formats code to maintain consistency across projects and teams, improving readability and reducing debates about code style.
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ECMAScript
This repo
This repository contains the source for the current draft of ECMA-262, the ECMAScript® Language Specification.
This source is processed to obtain a human-readable version, which you can view here.
If you want to explore how the specification was written, you can also view the source with its history in searchfox.
Current Proposals
Proposals follow the TC39 process and are tracked in the proposals repository.
Contributing New Proposals
Please see Contributing to ECMAScript for the most up-to-date information on contributing proposals to this standard.
Developing the Specification
After cloning, do npm install to set up your environment. You can then do npm run build to build the spec or npm run watch to set up a continuous build. The results will appear in the out directory, which you can use npm run clean to delete.
Community
- ES discourse: Forum for ECMAScript discussion and questions
- Matrix: Chat
Top Related Projects
HTML Standard
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
Node.js JavaScript runtime ✨🐢🚀✨
🐠 Babel is a compiler for writing next generation JavaScript.
Find and fix problems in your JavaScript code.
Prettier is an opinionated code formatter.
Convert designs to code with AI
Introducing Visual Copilot: A new AI model to turn Figma designs to high quality code using your components.
Try Visual Copilot