I've found myself (once again) polluting the `Function.prototype` with a lazy method that, once invoked, grants that the returned bound function is always the same, per context.
# Use Case It's still a common footgun to add events either via `context.method` or via `context.method.bind(context)`, where the former footgan would invoke `method` with a global context/undefined instead of the expected context, while the latter would make it impossible to ever remove that listener later on. It's also common to use methods for timers sensitive things, and it's indeed not by accident that `console` got "self bound", or provided as namespace, when it used to throw if `setTimeout(console.log, 100, value)` was used, for example. # Proposal Provide a lazy `bindContext` method that grants that if a method/function bound the same context before, it always returns the same reference. # Implementation / Polyfill (lazy version) ```js Function.prototype.bindContext = function (context) { const _ = new WeakMap; this.bindContext = bindContext; return bindContext.call(this, context); function bindContext(context) { if (!_.has(context)) _.set(context, this.bind(context)); return _.get(context); } }; ``` # Implementation details As the method suggest, and differently from `bind`, `bindContext` accepts only one argument, and it should throw with any context that is primitive (boolean, number, string, undefined, null), like any WeakMap key would throw as well. # Why not user-land / libraries / helpers Because standardizing a well-known/needed utility to not footgun common patterns would make the debate regarding global prototypes pollution irrelevant, as it's the standard that helps us out. In a few words, this might erase tons of common mistakes, but it also could be simplified within some helper/library, as long as not all of them need to include the proposed polyfill through a package or another. Thanks for consideration 👋
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