Introduction
ES5 and ES6 refer to different versions of the ECMAScript standard, which is a scripting language specification that serves as the foundation for several languages, including JavaScript. The evolution from ES5 to ES6 (also known as ECMAScript 2015) brought many changes and improvements. Here's a comparison between the two:
let .1 and const (declaring variables)
ES5: The main way to define variables is to use var It was.
ES6: Introduction let To define block-based variables and const To define block-based constant variables.
2. Template Literals
ES5: Strings using + They were connected.
var name = "John";
var greeting = "Hello, " + name + "!";ES6: String patterns were introduced.
let name = "John";
let greeting = `Hello, ${name}!`;Arrow Functions .3
ES5:
function(x) {
return x * x;
}ES6: Arrow functions were introduced, providing a shorter notation for writing functions.
x => x * x;
4. Classes
ES5: Prototypal inheritance was used to simulate the behavior of classes.
ES6: Keyword class It was introduced for object-oriented programming.
5. Enhanced Object Literals
ES5: Objects were defined by key-value pairs.
ES6: Provides a shorter notation for defining objects.
let name = "John";
let obj = {name}; // Equivalent to {name: name}6. Destructuring
ES5: There was no direct method.
ES6: It is now possible to extract multiple properties from an object or array in a more concise manner.
let person = { firstName: "John", lastName: "Doe" };
let { firstName, lastName } = person;7. Default values, Rest and Spread
ES5: Managing default, rest, or spread values was done manually.
ES6: Default values for function parameters, parameter ...rest To collect arguments and operator ...spread Introduced to expand an array or object.
8. Modules
ES5: There was no native module system. Developers used third-party solutions like CommonJS or AMD.
ES6: Native module system using import and export Introduced.
9. Promises
ES5: Callbacks were used for asynchronous operations.
ES6: Promises were introduced to manage asynchronous operations in a more structured way.
10. for-of loop
ES5: To iterate over arrays use loops. for Or forEach It was used.
ES6: Ring for-of It was introduced for iterating over iterable objects.
Set, Map, WeakSet, WeakMap 11
ES5: There was no direct equivalent.
ES6: These types of collections were introduced for data management.
12. Symbol type
ES5: There was no such thing.
ES6: Type Symbol Introduced to create unique identifiers.
13. Array and Object Methods
ES5: A limited set of methods.
ES6: New methods such as Array.from, Array.of, Object.assign And many others were introduced.
14. Parameter Management
ES5: Parameters using object arguments Access was granted.
ES6: Direct support for parameter management using rest, default and spread.
Result
This is a high-level comparison. The transition from ES5 to ES6 brought many changes and improvements that made the JavaScript language significantly richer. Over time, subsequent versions (such as ES7/ES2016 and later) added more features to the language.
