Dynamic method for speed optimisation

[kung foo man]

I am currently porting some JavaScript code and I don't know the best way to port over such code:

		function verySlowCalculationOnlyDoThisOnce() {
    console.log("logging slow calculation");
    return "bye";
}

Test = function(name) {
    this.name = name;
}

Object.assign(Test.prototype, {
    hello: function() {
        console.log("hello " + this.name)
    },

    bye: (function() {
        var byeMessage = verySlowCalculationOnlyDoThisOnce();
        return function() {
            return byeMessage + ", " + this.name + "!";
        }
    }())
}) 
	

The bye method basically prepares a part of the return value only once, every test = new Test("you") will reuse the result of the slow function.

How to rewrite such code for TypeScript?

The actual real life example is this:

https://github.com/playcanvas/engine...4.js#L418-L452

The three Vec3 are allocated once to prevent garbage collection.