Missing polyfills

• ES BigInt can't be polyfilled since it requires changes in the behavior of operators, you can find more info here. You could try to use JSBI.
• ES Proxy can't be polyfilled, you can try to use proxy-polyfill which provides a very small subset of features.
• ES String#normalize is not a very useful feature, but this polyfill will be very large. If you need it, you can use unorm.
• ECMA-402 Intl is missing because of its size. You can use these polyfills.
• fetch is not polyfilled: it depends on the networking of the platform, and now it's natively available in all modern browsers, Node.js 18+, Deno and Bun. For legacy engines, you can use, for example, this polyfill.
• ES WeakRef and FinalizationRegistry can't be polyfilled since they require integration with the garbage collector.
• ES SharedArrayBuffer and Atomics can't be polyfilled since they require memory shared between threads.
• ES resizable ArrayBuffer, growable SharedArrayBuffer and Float16Array are not polyfilled. Math.f16round and DataView methods for float16 values are polyfilled.
• Some new ES RegExp syntax, like lookbehind assertions or d and v flags, is not polyfilled.