[Fix] parse: preserve whitespace in comments

Fixes #6

Author: ljharb

parse.js

@@ -31,6 +31,24 @@ for (var i = 0; i < 4; i++) {
 }
 var startsWithToken = new RegExp('^' + TOKEN);
 
+function matchAll(s, r) {
+	var origIndex = r.lastIndex;
+
+	var matches = [];
+	var matchObj;
+
+	while ((matchObj = r.exec(s))) {
+		matches.push(matchObj);
+		if (r.lastIndex === matchObj.index) {
+			r.lastIndex += 1;
+		}
+	}
+
+	r.lastIndex = origIndex;
+
+	return matches;
+}
+
 function parseInternal(string, env, opts) {
 	if (!opts) {
 		opts = {};
@@ -43,9 +61,9 @@ function parseInternal(string, env, opts) {
 		'(' + BAREWORD + '|' + SINGLE_QUOTE + '|' + DOUBLE_QUOTE + ')+'
 	].join('|'), 'g');
 
-	var matches = string.match(chunker);
+	var matches = matchAll(string, chunker);
 
-	if (!matches) {
+	if (matches.length === 0) {
 		return [];
 	}
 	if (!env) {
@@ -68,8 +86,9 @@ function parseInternal(string, env, opts) {
 		return pre + r;
 	}
 
-	return matches.filter(Boolean).map(function (s, j, match) {
-		if (commented) {
+	return matches.map(function (match) {
+		var s = match[0];
+		if (!s || commented) {
 			return void undefined;
 		}
 		if (controlRE.test(s)) {
@@ -157,7 +176,7 @@ function parseInternal(string, env, opts) {
 				return { op: s };
 			} else if (hash.test(c)) {
 				commented = true;
-				var commentObj = { comment: s.slice(i + 1) + match.slice(j + 1).join(' ') };
+				var commentObj = { comment: string.slice(match.index + i + 1) };
 				if (out.length) {
 					return [out, commentObj];
 				}
@@ -177,6 +196,7 @@ function parseInternal(string, env, opts) {
 
 		return out;
 	}).reduce(function (prev, arg) { // finalize parsed arguments
+		// TODO: replace this whole reduce with a concat
 		return typeof arg === 'undefined' ? prev : prev.concat(arg);
 	}, []);
 }

test/comment.js

@@ -6,11 +6,11 @@ var parse = require('../').parse;
 test('comment', function (t) {
 	t.same(parse('beep#boop'), ['beep', { comment: 'boop' }]);
 	t.same(parse('beep #boop'), ['beep', { comment: 'boop' }]);
-	t.same(parse('beep # boop'), ['beep', { comment: 'boop' }]);
-	t.same(parse('beep # > boop'), ['beep', { comment: '> boop' }]);
-	t.same(parse('beep # "> boop"'), ['beep', { comment: '"> boop"' }]);
+	t.same(parse('beep # boop'), ['beep', { comment: ' boop' }]);
+	t.same(parse('beep # > boop'), ['beep', { comment: ' > boop' }]);
+	t.same(parse('beep # "> boop"'), ['beep', { comment: ' "> boop"' }]);
 	t.same(parse('beep "#"'), ['beep', '#']);
 	t.same(parse('beep #"#"#'), ['beep', { comment: '"#"#' }]);
-	t.same(parse('beep > boop # > foo'), ['beep', { op: '>' }, 'boop', { comment: '> foo' }]);
+	t.same(parse('beep > boop # > foo'), ['beep', { op: '>' }, 'boop', { comment: ' > foo' }]);
 	t.end();
 });

test/parse.js

@@ -24,5 +24,8 @@ test('parse shell commands', function (t) {
 	t.same(parse("x bl^'a^'h'", {}, { escape: '^' }), ['x', "bl'a'h"]);
 	t.same(parse('abcH def', {}, { escape: 'H' }), ['abc def']);
 
+	t.deepEqual(parse('# abc  def  ghi'), [{ comment: ' abc  def  ghi' }], 'start-of-line comment content is unparsed');
+	t.deepEqual(parse('xyz # abc  def  ghi'), ['xyz', { comment: ' abc  def  ghi' }], 'comment content is unparsed');
+
 	t.end();
 });