Multiple passes?

[boopathi]

Are there situations that we might need multiple passes for better minification ?

For example, one plugin might transform

if (a) foo (x) : foo (y);
//to
a ? foo (x) : foo (y)

and another plugin might transform

//to
foo (a ? x : y);

// or even,
x ? foo(a) : foo(b)
//to
foo (x ? a : b)

and another one could remove this as pure expression statement. or modify it differently. I'm not able to think about it.

So the order of plugins in the preset will matter, and we say (with plugins- a and b) the order is a, b, and another particular transformation might require the order to be b, a. So, should we explore multiple passes. I'm not sure if this is a problem. Just asking if there are situations that you faced like this.

[fregante]

This is definitely a problem in a lot of other optimization software I used and babel-minify is no exception; I listed a couple of already-existing sorting issues here: #25 (comment) (the last two points at the end of Edit 2)

[boopathi]

#317 Simplify and DCE order

[kangax]

A brute force solution would be to add a preset option that simply does 2 passes. When I tested this a while ago I also saw that sometimes 3 passes can increase size even more. Not sure how to deal with this. How to strike balance between transformation time and size, where a tiny improvement can cause 2x or 3x longer times.

[boopathi]

3 passes can increase size even more

this should be the mangler

[boopathi]

#422 Simplify after DCE

[vigneshshanmugam]

lets take advantage of the plugin ordering option babel/babel#5735