What are the new features of es6

The new features of es6 are: 1. Block-level scope, variables can be declared in block-level scope; 2. Arrow function, a new way of declaring functions; 3. Destructuring assignment, a method of declaring functions from A language that extracts values ​​from an array or object and assigns them to variables; 4. Default parameters, allowing default values ​​to be provided for parameters when defining functions; 5. Extension operators, which can expand arrays or objects and extract elements; 6. Template string; 7. Classes and modules; 8. Iterators and generators; 9. Promise objects; 10. Modular import and export, etc.

The operating environment of this tutorial: Windows 10 system, ECMAScript version 6, Dell G3 computer.

ES6 (ECMAScript 6) is the sixth version of the JavaScript standard, officially released in 2015. Compared with previous versions, ES6 introduces many new syntax and features, making JavaScript programming more convenient and elegant. This article will introduce some important features in ES6.

1. Block-level scope: ES6 introduced the let and const keywords, which can declare variables in the block-level scope. Variables declared using let are only valid within the current scope, avoiding the problems of variable promotion and global naming conflicts. A constant declared using const is a read-only variable. Once assigned, it cannot be changed.

2. Arrow function: Arrow function is a new function declaration method in ES6, using arrow (=>) to replace the traditional function keyword. The arrow function has a more concise syntax and automatically binds the context, solving the problem of this pointing in the callback function.

3. Destructuring assignment: Destructuring assignment is a syntax that extracts values ​​from an array or object and assigns them to variables. In ES6, you can use destructuring assignment syntax to quickly obtain elements in an array or object, simplifying code writing and data exchange.

4. Default parameters: ES6 introduces default parameters for functions, allowing default values ​​to be provided for parameters when the function is defined. If no parameters are passed when called, default values ​​will be used. This simplifies the use of the function and allows you to pass some of the parameters instead of all of them.

5. Spread operator: The spread operator can expand an array or object and extract its elements. In function calls or array and object literals, use the ... syntax to expand an array or object into individual elements, or to combine multiple elements into an array or object.

6. Template string: Template string is a more convenient way to splice strings. Backticks (`) are used to define strings, and variables and expressions can be inserted into them, which improves the efficiency of the code. Readability and maintainability.

7. Classes and modules: ES6 introduces the syntactic sugar of classes, making object-oriented programming more concise and easier to use. Classes can inherit through the extends keyword, and use the super keyword to call methods of the parent class. In addition, ES6 also introduces the concept of modularity, and modules can be easily imported and exported through the import and export keywords.

8. Iterators and generators: ES6 introduces the concepts of iterators and generators, which can simplify the complexity of processing collections and asynchronous programming. An iterator is an object that contains a next() method that returns values ​​one by one in a defined order. The generator is a special function that can save the state through the yield keyword and resume execution when needed.

9. Promise object: Promise is a solution to asynchronous programming that can avoid callback hell and provide better error handling. Promise objects can represent the final completion or failure of an asynchronous operation, and can chain call and process multiple asynchronous operations.

10. Modular import and export: The modular syntax in ES6 can better organize and manage code, providing import and export keywords, as well as the export default keyword to import and export modules.

The above only introduces some important features of ES6. In fact, ES6 also contains many other new features, such as Map and Set data structures, new syntax for iteration and deconstruction, and new methods for strings and arrays. etc. These new features make JavaScript programming more modern and efficient, promoting the development and progress of the JavaScript ecosystem. Learning and using the new features of ES6 will help improve the efficiency and quality of JavaScript programming.

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