How to minify nested properties

I'm using terser-js to minify my code.

The output:

a.prototype.a = ...
a.prototype.b = ...
a.prototype.c = ...

What I want:

var h = a.prototype
h.a = ...
h.b = ...
h.c = ...

Note that I can't write it by hand because the inputs are generated from TypeScript.

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