ECMAScript 5 (2009)
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Strict Mode (
'use strict'): Enforces better coding practices.
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Array Methods:
forEach, map, filter, reduce, some, every.
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Object Methods:
Object.keys(), Object.create().
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Getter/Setter Properties: Define computed properties.
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JSON Support:
JSON.parse(), JSON.stringify().
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bind() Method: Binds this to a function.
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Property Descriptors: Control property attributes like
writable, configurable.
ECMAScript 6 (ES6) - 2015
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let and const: Block-scoped variables.
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Arrow Functions (
=>): Shorter syntax for functions.
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Template Literals: String interpolation using backticks.
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Default Parameters: Function parameters with default values.
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Destructuring: Extract values from objects/arrays.
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Spread (
...) and Rest Parameters: Expanding and collecting values.
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Classes (
class): Syntactic sugar over constructor functions.
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Modules (
import / export): Native module support.
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Promises: Handle asynchronous operations.
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Map and Set: New data structures.
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Generators (
function*): Pause and resume execution.
ECMAScript 7 (ES7) - 2016
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Exponentiation Operator (
**): 2 ** 3 === 8.
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Array.prototype.includes(): Check if an array contains a value.
ECMAScript 8 (ES8) - 2017
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Async/Await: Simplifies working with Promises.
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Object Entries and Values:
Object.entries(), Object.values().
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String Padding:
padStart(), padEnd().
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Trailing Commas in Function Parameters: Avoid syntax errors in version control.
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Shared Memory & Atomics: Multi-threaded JS via
SharedArrayBuffer.
ECMAScript 9 (ES9) - 2018
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Rest/Spread in Objects:
{ ...obj }.
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Promise.prototype.finally(): Runs after a Promise resolves/rejects.
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Asynchronous Iteration (
for await...of): Async iterators.
ECMAScript 10 (ES10) - 2019
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Array.prototype.flat() & flatMap(): Flatten nested arrays.
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Object.fromEntries(): Convert key-value pairs into objects.
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Optional Catch Binding:
catch { } without explicitly defining an error variable.
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String Trim Methods:
trimStart(), trimEnd().
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Symbol Description:
Symbol('desc').description.
ECMAScript 11 (ES11) - 2020
-
BigInt (
123n): Large integer support.
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Dynamic
import(): Asynchronous module loading.
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Nullish Coalescing (
??): x = a ?? 'default'.
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Optional Chaining (
?.): Safe property access.
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Promise.allSettled(): Resolves after all Promises settle.
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String
matchAll(): Returns all matches in a string.
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Global
This (globalThis): Unified global object access.
ECMAScript 12 (ES12) - 2021
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Numeric Separators (
1_000_000): Improves readability.
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replaceAll(): Replace all instances in a string.
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WeakRefs & FinalizationRegistry: Manage memory manually.
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Logical Assignment (
&&=, ||=, ??=): Shorter conditional assignments.
ECMAScript 13 (ES13) - 2022
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at() Method: Access array elements via negative indices.
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Object.hasOwn(): Better alternative to hasOwnProperty.
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Class Private Fields & Methods:
#privateField.
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Top-Level
await: await outside async functions.
ECMAScript 14 (ES14) - 2023
-
Array
findLast() & findLastIndex(): Find last matching element.
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Set Methods:
union(), intersection(), difference(), symmetricDifference().
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Hashbang (
#!) in Scripts: Support for Unix-style shebangs.
-
Symbols as WeakMap Keys: Improved memory handling.
Upcoming Features (ESNext)
-
Explicit Resource Management (
using): Auto-dispose resources.
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Temporal API: Improved date/time handling.
-
Pipeline Operator (
|>): Streamline function chaining.
