support dumping AST

[alexlamsl]

closes #769

#1878 (comment)

[kzc]

Can you please change this to:

var skip_keys = [ "cname", "enclosed", ... ];
function skip_key(key) { return skip_keys.indexOf(key) >= 0; }

as it's more efficient.

[alexlamsl]

I assume you meant function skip_key(...? 😮

[kzc]

indeed. corrected.

[alexlamsl]

Done in 4116731

[kzc]

perfect.

[kzc]

Wow - nice. Far simpler implementation than the dump AST patch.

[alexlamsl]

Wow - nice. Far simpler implementation than the dump AST patch.

I cheat by utilising the recursive nature of JSON.stringify()'s replacer 👻

[kzc]

This will make debugging infinitely easier.

[alexlamsl]

@kzc reading your patch at #769 (comment) again, I noticed I've missed reordering of AST_Binary's properties.

[kzc]

I noticed I've missed reordering of AST_Binary's properties.

Thanks. Makes it much easier to read the AST output.

[kzc]

Something is not quite right with the latest version of this PR:

$ bin/uglifyjs --self -mc passes=3 -o ast
bin/uglifyjs:380
    return skip_keys.indexOf(key) >= 0;
                    ^

TypeError: Cannot read property 'indexOf' of undefined

Would you mind adding at least one AST dump mocha test?

[kzc]

This is a workaround for the bug above:

bin/uglifyjs --self -mc passes=3 | bin/uglifyjs -o ast

[alexlamsl]

That's one strange bug indeed - let me investigate, then put in a quick mocha test.

Edit: yeah, I'm being an idiot...

[alexlamsl]

Something is not quite right with the latest version of this PR:

Should be fixed by 1040110, alongside a mocha test.

[kzc]

Odd - why would moving the skip_keys array to the top fix the problem for some cases?

[alexlamsl]

Reading from process.stdin is asynchronous, i.e. run() gets called within the event loop, which means the rest of bin/uglifyjs gets to be evaluated before it.

The previous version of this PR also works because it does not contain var skip_keys, so there wasn't any issue with execution order.

[kzc]

Reading from process.stdin is asynchronous

Thanks. It's obvious in hindsight.

[kzc]

This feature works great - best thing since sliced bread.