Hmm, can we be more precise about the value of start and end here?

Preferably with the source code under test spans multiple lines so we can reasonably sure the fields have been populated with sensible values?

This looks somewhat similar to embed_tokens() which is use extensively throughout this file. Would you mind considering whether we can reuse that in this case as well?

I do not mind, however this is beyond my current JS abilities. What I have tried is:

                a.push(new AST_ObjectGetter({
                    start : start,
                    key   : as_atom_node(),
                    value : embed_tokens(function(){function_(AST_Accessor)}),
                    end   : prev()
                }));

This resulted in a parse error. If you can advise me how do to his properly, I will be glad to implement it.

I'm typing from mobile, but this might work:

var createAccessor = embed_tokens(function() {
  return function_(AST_Accessor);
});

If not, I'll be back in a couple of hours and will take a look then.

Tried that (and thought: "Silly me. off course I have to return in JS, this is not Scala "), but I still get the parsing error:

'SyntaxError: Unexpected token punc «(», expected punc «,»'

My code was:

            var createAccessor = function() {embed_tokens(function() {
                return function_(AST_Accessor);
            })};

I'm confused - did you try my suggestion or yours? Yours has an extra function() {...} wrapped around it.

I tried both, first what you wrote, then this - I was afraid your solution executes outside of the get / set scopes, now I see it does not - it returns a function, and executes nothing on its own.

Thanks for clarifying. I'll have a closer look when I get home.

I have tried your solution once again and I see its error is different. It outputs no parsing error, only the test is not passed, with assertion:

AssertionError: 22 == 12

What is the correct result - In the test code var obj = { get latest() { return undefined; } }, where should the accessor node start? Pos. 22 is right behind latest, pos. 12 is the beginning of get.

Checking http://lisperator.net/uglifyjs/ast, I think 22 makes more sense as a result, AST_Accessor is a child of AST_Lambda, and has no name. I am committing your implementation and adjusting the test,

@OndrejSpanel thanks for the detailed investigation 👍

Doesn't the AST_Accessor start at 12 - the beginning of the get keyword?

get latest() { return undefined; }

I think is is a matter of opinion. I will try to explain why I think with it should start at 22:

The AST hierarchy is:
AST_ObjectProperty contains

• key of type AST_KeySymbolRef
• value of type AST_Accessor

As key is what contains the property name, I think it makes a sense to let the AST_Accessor to start after it. Perhaps its name is a bit misleading and it should be called something like AST_AccessorBody, but I doubt you will want to break AST compatibility because of this.

I see. For what it's worth, acorn reports the FunctionExpression start at 22 as well.

What is the start/end for the AST_ObjectProperty for get latest() { return undefined; }?

The start/end for the AST_ObjectProperty is 12 / 46.

Can you please check the AST_ObjectProperty start/end, as well as the AST_KeySymbolRef start/end in the test as well?

I could not use the same way as before, as Walker is not visiting the key node, therefore it needs to be accessed from its parent. I like it more this way anyway.

Technically you don't need a tree walker at all. You could access each node from the toplevel ast node directly.