Question
Answer and Explanation
Chrome version 94 primarily uses the ECMAScript 2020 (ES11) specification for JavaScript. However, it's important to note that browser JavaScript engines, like Chrome's V8, often implement features from newer ECMAScript specifications before they are officially finalized. Therefore, Chrome 94 might also include some features from ECMAScript 2021 (ES12) and even experimental features.
Here's a breakdown:
1. ECMAScript 2020 (ES11): This is the core JavaScript version that Chrome 94 is built upon. It includes features like:
- `Promise.allSettled()`: Returns a promise that resolves after all of the given promises have either resolved or rejected.
- `String.prototype.matchAll()`: Returns an iterator of all results matching a string against a regular expression.
- `import()`: Dynamic import syntax for loading modules on demand.
- `BigInt`: A new primitive type for arbitrary-precision integers.
- `globalThis`: A global object that provides a consistent way to access the global scope across different environments.
- Nullish Coalescing Operator (`??`): Returns the right-hand side operand when the left-hand side is null or undefined.
- Optional Chaining Operator (`?.`): Allows accessing properties of potentially null or undefined objects without causing errors.
2. ECMAScript 2021 (ES12) Features: Chrome 94 likely includes some features from ES12, such as:
- `String.prototype.replaceAll()`: Replaces all occurrences of a string with another string.
- `Promise.any()`: Returns a promise that resolves as soon as one of the given promises resolves.
- Logical Assignment Operators (`||=`, `&&=`, `??=`): Combines logical operations with assignment.
3. Experimental Features: Chrome often includes experimental features that are not yet part of any official ECMAScript specification. These features are usually behind flags and may not be stable.
It's important to note that the specific features supported can vary slightly between different builds of Chrome 94. To get the most accurate information, you can check the V8 release notes for the version of V8 that is included in Chrome 94. You can also use websites like caniuse.com to check the browser compatibility of specific JavaScript features.
In summary, while Chrome 94 is primarily based on ECMAScript 2020, it also includes some features from later specifications and experimental features. Developers should always test their code across different browsers and versions to ensure compatibility.