Flight by Twitter: "Mixins
A mixin defines a set of functionality that is useful to more than one object. Flight comes with built-in support for functional mixins, including protection against unintentional overrides and duplicate mixins. While classical JavaScript patterns support only single inheritance, a component (or other object) can have multiple mixins applied to it. Moreover mixins requires a fraction of the boilerplate required to form traditional classical hierarchies out of constructor-prototypes hybrids, and don't suffer the leaky abstractions of the latter ('super', 'static', 'const' etc.)
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