ECMAScript 6 compatibility shims for legacy JavaScript engines, providing modern ES6 features in older environments.
ES6 Shim is a JavaScript compatibility library that provides shims for ECMAScript 6 features in legacy JavaScript engines. It solves the problem of inconsistent or missing ES6 support across different browsers and Node.js versions by implementing modern JavaScript APIs like Promises, Maps, Sets, and new array/string methods in environments where they aren't natively available.
JavaScript developers working with legacy browsers or older Node.js versions who need to use ES6 features while maintaining cross-environment compatibility. It's particularly valuable for teams supporting Internet Explorer or other browsers with incomplete ES6 implementations.
Developers choose ES6 Shim because it provides comprehensive, spec-compliant implementations of ES6 features with a focus on correctness and safety. Unlike some polyfills, it avoids incorrect implementations and offers modular standalone shims, making it a reliable choice for production applications that need consistent ES6 behavior across all environments.
ECMAScript 6 compatibility shims for legacy JS engines
Open-Awesome is built by the community, for the community. Submit a project, suggest an awesome list, or help improve the catalog on GitHub.
Implements a wide array of ES6 features including Map, Set, Promise, and new string/array methods, as detailed in the 'Safe shims' section of the README.
Prioritizes correctness over polyfilling everything, avoiding incorrect shims like WeakMap and ensuring behavior matches the ES6 specification, as stated in the philosophy.
Offers individual npm packages for each feature, allowing developers to include only necessary shims, with many 'a standalone shim is also available' links in the README.
Enables subclassing of Map, Set, and Promise with proper prototype chain setup, with code examples provided in the README section on subclassing.
Does not include a WeakMap implementation because it's impossible to implement correctly in pure JavaScript, limiting completeness for ES6 features as admitted in the README.
String.prototype.normalize requires installing the separate 'unorm' package, adding complexity and an extra dependency, as noted in the README section on normalize.
Strongly recommends including es5-shim for broken ES5 implementations, increasing setup burden and bundle size, as emphasized in the installation instructions.
Polyfilling can introduce performance penalties compared to native implementations, especially for heavy features like Promises or collections, which may impact resource-constrained applications.