How TCO works

Let's compare two stack frames, one without TCO and the other with TCO. Let's have a look at the following code first:

function a(x){    y = x + 2;    return b(y);}function b(y){    z = y + 3;    return z;}console.log(a(1)); // 6

Once allocated to memory, without using TCO, the three stack frames from of the previous code would look like the following diagram:

A typical last-in, first-out (LIFO) call stack

Once value 6 is assigned to variable z, the stack frame is ready to be popped. In this case, stack frame 2 is kept entirely in memory only to keep the address of console.log(). This is where TCO can make a difference. If, before calling ...

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