Ubuntu环境下WebStorm的ES6语法兼容问题：无需use strict可行吗？

Hey there! Let's tackle your two ES6-related issues in WebStorm on Ubuntu one by one—no overly technical jargon, just practical fixes.

That SyntaxError: Block-scoped declarations (let, const, function, class) not yet... error pops up because your environment is defaulting to ES5 mode, which doesn't support block-scoped variables like let unless strict mode is enabled. If you don't want to add "use strict", here's how to get ES6 support natively:

• Upgrade your Node.js version: If you're running your code with Node.js, older versions (pre-v6.0) require strict mode for let/const. Grab an LTS version (like 18.x or newer)—these versions enable ES6 features by default, so you can use let without any extra strict mode declarations.
• Configure WebStorm's JavaScript version: Open WebStorm's Settings/Preferences (press Ctrl+Alt+S on Windows/Linux, Cmd+, on Mac), navigate to Languages & Frameworks → JavaScript, and set the JavaScript language version to ECMAScript 6 or higher (e.g., ECMAScript 2020+). This tells the IDE to recognize ES6 syntax and won't flag let as an error.
• Browser environment check: If you're running code in a browser, modern browsers (Chrome, Firefox, Edge, etc.) fully support ES6 let without strict mode. Just make sure you're not targeting super old browser versions—if you are, you might need a transpiler like Babel, but that's only necessary for legacy support.

The a ** 2 shorthand for Math.pow(a, 2) is an ES2016 (ES7) feature, not ES6. That's why WebStorm isn't picking it up by default. Here's how to fix it:

• Update your JavaScript language version in WebStorm: Head back to Settings/Preferences → Languages & Frameworks → JavaScript and set the version to ECMAScript 2016 or higher. This will make WebStorm recognize the exponentiation operator, resolve any red underlines, and even provide syntax hints for it.
• Upgrade WebStorm (if needed): If you're using an older version of WebStorm, it might lack full support for ES2016+ features. Updating to the latest stable release will ensure you have access to all modern JavaScript syntax support.

内容的提问来源于stack exchange，提问作者Svetoslav Nedelchev