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make comments output more robust (#2633)
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- improve handling of comments right after `return`
- retain comments after `OutputStream`
- preserve trailing comments
- fix handling of new line before comments
- handle comments around parentheses

fixes #88
fixes #112
fixes #218
fixes #372
fixes #2629
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@alexlamsl
alexlamsl committed Dec 21, 2017
1 parent 4113609 commit edb4e3b
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Showing 7 changed files with 401 additions and 90 deletions.
2 changes: 1 addition & 1 deletion lib/ast.js
View file
Expand Up @@ -87,7 +87,7 @@ function DEFNODE(type, props, methods, base) {
return ctor;
};

var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos nlb comments_before file raw", {
var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos nlb comments_before comments_after file raw", {
}, null);

var AST_Node = DEFNODE("Node", "start end", {
Expand Down
212 changes: 133 additions & 79 deletions lib/output.js
View file
Expand Up @@ -52,6 +52,7 @@ function is_some_comments(comment) {

function OutputStream(options) {

var readonly = !options;
options = defaults(options, {
ascii_only : false,
beautify : false,
Expand Down Expand Up @@ -199,6 +200,7 @@ function OutputStream(options) {
var might_need_space = false;
var might_need_semicolon = false;
var might_add_newline = 0;
var need_newline_indented = false;
var last = "";
var mapping_token, mapping_name, mappings = options.source_map && [];

Expand Down Expand Up @@ -257,6 +259,13 @@ function OutputStream(options) {
function print(str) {
str = String(str);
var ch = str.charAt(0);
if (need_newline_indented && ch) {
need_newline_indented = false;
if (ch != "\n") {
print("\n");
indent();
}
}
var prev = last.charAt(last.length - 1);
if (might_need_semicolon) {
might_need_semicolon = false;
Expand Down Expand Up @@ -427,6 +436,109 @@ function OutputStream(options) {
return OUTPUT;
};

function prepend_comments(node) {
var self = this;
var start = node.start;
if (!(start.comments_before && start.comments_before._dumped === self)) {
var comments = start.comments_before;
if (!comments) {
comments = start.comments_before = [];
}
comments._dumped = self;

if (node instanceof AST_Exit && node.value) {
var tw = new TreeWalker(function(node) {
var parent = tw.parent();
if (parent instanceof AST_Exit
|| parent instanceof AST_Binary && parent.left === node
|| parent.TYPE == "Call" && parent.expression === node
|| parent instanceof AST_Conditional && parent.condition === node
|| parent instanceof AST_Dot && parent.expression === node
|| parent instanceof AST_Sequence && parent.expressions[0] === node
|| parent instanceof AST_Sub && parent.expression === node
|| parent instanceof AST_UnaryPostfix) {
var text = node.start.comments_before;
if (text && text._dumped !== self) {
text._dumped = self;
comments = comments.concat(text);
}
} else {
return true;
}
});
tw.push(node);
node.value.walk(tw);
}

if (current_pos == 0) {
if (comments.length > 0 && options.shebang && comments[0].type == "comment5") {
print("#!" + comments.shift().value + "\n");
indent();
}
var preamble = options.preamble;
if (preamble) {
print(preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
}
}

comments = comments.filter(comment_filter, node);
if (comments.length == 0) return;
var last_nlb = /(^|\n) *$/.test(OUTPUT);
comments.forEach(function(c, i) {
if (!last_nlb) {
if (c.nlb) {
print("\n");
indent();
last_nlb = true;
} else if (i > 0) {
space();
}
}
if (/comment[134]/.test(c.type)) {
print("//" + c.value + "\n");
indent();
last_nlb = true;
} else if (c.type == "comment2") {
print("/*" + c.value + "*/");
last_nlb = false;
}
});
if (!last_nlb) {
if (start.nlb) {
print("\n");
indent();
} else {
space();
}
}
}
}

function append_comments(node, tail) {
var self = this;
var token = node.end;
if (!token) return;
var comments = token[tail ? "comments_before" : "comments_after"];
if (comments && comments._dumped !== self) {
comments._dumped = self;
comments.filter(comment_filter, node).forEach(function(c, i) {
if (need_newline_indented || c.nlb) {
print("\n");
indent();
need_newline_indented = false;
} else if (i > 0 || !tail) {
space();
}
if (/comment[134]/.test(c.type)) {
print("//" + c.value);
need_newline_indented = true;
} else if (c.type == "comment2") {
print("/*" + c.value + "*/");
}
});
}
}

var stack = [];
return {
get : get,
Expand Down Expand Up @@ -464,7 +576,8 @@ function OutputStream(options) {
with_square : with_square,
add_mapping : add_mapping,
option : function(opt) { return options[opt] },
comment_filter : comment_filter,
prepend_comments: readonly ? noop : prepend_comments,
append_comments : readonly ? noop : append_comments,
line : function() { return current_line },
col : function() { return current_col },
pos : function() { return current_pos },
Expand Down Expand Up @@ -500,9 +613,10 @@ function OutputStream(options) {
use_asm = active_scope;
}
function doit() {
self.add_comments(stream);
stream.prepend_comments(self);
self.add_source_map(stream);
generator(self, stream);
stream.append_comments(self);
}
stream.push_node(self);
if (force_parens || self.needs_parens(stream)) {
Expand All @@ -519,77 +633,10 @@ function OutputStream(options) {

AST_Node.DEFMETHOD("print_to_string", function(options){
var s = OutputStream(options);
if (!options) s._readonly = true;
this.print(s);
return s.get();
});

/* -----[ comments ]----- */

AST_Node.DEFMETHOD("add_comments", function(output){
if (output._readonly) return;
var self = this;
var start = self.start;
if (start && !start._comments_dumped) {
start._comments_dumped = true;
var comments = start.comments_before || [];

// XXX: ugly fix for https://github.com/mishoo/UglifyJS2/issues/112
// and https://github.com/mishoo/UglifyJS2/issues/372
if (self instanceof AST_Exit && self.value) {
self.value.walk(new TreeWalker(function(node){
if (node.start && node.start.comments_before) {
comments = comments.concat(node.start.comments_before);
node.start.comments_before = [];
}
if (node instanceof AST_Function ||
node instanceof AST_Array ||
node instanceof AST_Object)
{
return true; // don't go inside.
}
}));
}

if (output.pos() == 0) {
if (comments.length > 0 && output.option("shebang") && comments[0].type == "comment5") {
output.print("#!" + comments.shift().value + "\n");
output.indent();
}
var preamble = output.option("preamble");
if (preamble) {
output.print(preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
}
}

comments = comments.filter(output.comment_filter, self);

// Keep single line comments after nlb, after nlb
if (!output.option("beautify") && comments.length > 0 &&
/comment[134]/.test(comments[0].type) &&
output.col() !== 0 && comments[0].nlb)
{
output.print("\n");
}

comments.forEach(function(c){
if (/comment[134]/.test(c.type)) {
output.print("//" + c.value + "\n");
output.indent();
}
else if (c.type == "comment2") {
output.print("/*" + c.value + "*/");
if (start.nlb) {
output.print("\n");
output.indent();
} else {
output.space();
}
}
});
}
});

/* -----[ PARENTHESES ]----- */

function PARENS(nodetype, func) {
Expand Down Expand Up @@ -811,14 +858,21 @@ function OutputStream(options) {
self.body.print(output);
output.semicolon();
});
function print_bracketed(body, output, allow_directives) {
if (body.length > 0) output.with_block(function(){
display_body(body, false, output, allow_directives);
});
else output.print("{}");
function print_bracketed(self, output, allow_directives) {
if (self.body.length > 0) {
output.with_block(function() {
display_body(self.body, false, output, allow_directives);
});
} else {
output.print("{");
output.with_indent(output.next_indent(), function() {
output.append_comments(self, true);
});
output.print("}");
}
};
DEFPRINT(AST_BlockStatement, function(self, output){
print_bracketed(self.body, output);
print_bracketed(self, output);
});
DEFPRINT(AST_EmptyStatement, function(self, output){
output.semicolon();
Expand Down Expand Up @@ -913,7 +967,7 @@ function OutputStream(options) {
});
});
output.space();
print_bracketed(self.body, output, true);
print_bracketed(self, output, true);
});
DEFPRINT(AST_Lambda, function(self, output){
self._do_print(output);
Expand Down Expand Up @@ -1044,7 +1098,7 @@ function OutputStream(options) {
DEFPRINT(AST_Try, function(self, output){
output.print("try");
output.space();
print_bracketed(self.body, output);
print_bracketed(self, output);
if (self.bcatch) {
output.space();
self.bcatch.print(output);
Expand All @@ -1061,12 +1115,12 @@ function OutputStream(options) {
self.argname.print(output);
});
output.space();
print_bracketed(self.body, output);
print_bracketed(self, output);
});
DEFPRINT(AST_Finally, function(self, output){
output.print("finally");
output.space();
print_bracketed(self.body, output);
print_bracketed(self, output);
});

/* -----[ var/const ]----- */
Expand Down
15 changes: 9 additions & 6 deletions lib/parse.js
View file
Expand Up @@ -317,11 +317,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
}
if (!is_comment) {
ret.comments_before = S.comments_before;
S.comments_before = [];
// make note of any newlines in the comments that came before
for (var i = 0, len = ret.comments_before.length; i < len; i++) {
ret.nlb = ret.nlb || ret.comments_before[i].nlb;
}
ret.comments_after = S.comments_before = [];
}
S.newline_before = false;
return new AST_Token(ret);
Expand Down Expand Up @@ -1280,9 +1276,16 @@ function parse($TEXT, options) {
case "(":
next();
var ex = expression(true);
[].push.apply(start.comments_before, ex.start.comments_before);
ex.start.comments_before = start.comments_before;
start.comments_after = ex.start.comments_after;
ex.start = start;
ex.end = S.token;
expect(")");
var end = prev();
end.comments_before = ex.end.comments_before;
[].push.apply(ex.end.comments_after, end.comments_after);
end.comments_after = ex.end.comments_after;
ex.end = end;
return subscripts(ex, allow_calls);
case "[":
return subscripts(array_(), allow_calls);
Expand Down
2 changes: 1 addition & 1 deletion lib/utils.js
View file
Expand Up @@ -324,7 +324,7 @@ function first_in_statement(stack) {
if (p instanceof AST_Statement && p.body === node)
return true;
if ((p instanceof AST_Sequence && p.expressions[0] === node) ||
(p instanceof AST_Call && p.expression === node && !(p instanceof AST_New) ) ||
(p.TYPE == "Call" && p.expression === node ) ||
(p instanceof AST_Dot && p.expression === node ) ||
(p instanceof AST_Sub && p.expression === node ) ||
(p instanceof AST_Conditional && p.condition === node ) ||
Expand Down

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