Support autofix for disallow-trailing-whitespace

lib/rules/disallow-trailing-whitespace.js

@@ -64,13 +64,89 @@ module.exports.prototype = {
 
     check: function(file, errors) {
         var ignoreEmptyLines = this._ignoreEmptyLines;
+        var lineTokens = file._tokensByLineIndex;
+        var lines = file.getLines().length;
+        var lastLine = 1;
 
-        var lines = file.getLines();
-        for (var i = 0, l = lines.length; i < l; i++) {
-            if (lines[i].match(/\s$/) && !(ignoreEmptyLines && lines[i].match(/^\s*$/))) {
-                errors.add('Illegal trailing whitespace', i + 1, lines[i].length);
+        function checkTokenWhiteSpace(token) {
+            var whitespace = token.whitespaceBefore;
+            var subLines = whitespace.split(file.getLineBreakStyle());
+
+            for (var l = 0; l < subLines.length; l++) {
+                var subLine = subLines[l];
+
+                if (l === subLines.length - 1 && token.type !== 'EOF') {
+                    // skip check if it is a last whitespace line and not eof
+                    break;
+                }
+
+                var isEmptyLine =
+                    l  || // not first sub line (since there's prev tokens on line)
+                        token._tokenIndex === 0 && l === 0 // first token exception
+                ;
+
+                if (subLine.length && !(ignoreEmptyLines && isEmptyLine)) {
+                    errors.assert.emit('error', {
+                        message: 'Illegal trailing whitespace',
+                        line: lastLine + l,
+                        column: subLine.length,
+                        fixed: true
+                    });
+                    subLines[l] = '';
+                }
             }
+
+            token.whitespaceBefore = subLines.join(file.getLineBreakStyle());
         }
-    }
 
+        for (var i = 1; i <= lines; i++) {
+            if (!lineTokens[i]) {
+                continue;
+            }
+
+            var line = lineTokens[i];
+            // check first line token
+            var token = line[0];
+            checkTokenWhiteSpace(token);
+
+            // check last line token
+            token = line[line.length - 1];
+            if (token.isComment && token.type === 'Line') {
+                // line comment
+                if (token.value.match(/\s+$/)) {
+                    errors.assert.emit('error', {
+                        message: 'Illegal trailing whitespace',
+                        line: i,
+                        column: token.loc.end.column,
+                        fixed: true
+                    });
+
+                    token.value = token.value.replace(/\s+$/, '');
+                }
+            } else if (token.isComment && token.type === 'Block') {
+                // block comment
+                var subLines = token.value.split(file.getLineBreakStyle());
+                for (var l = 0; l < subLines.length - 1; l++) {
+                    var subLine = subLines[l];
+
+                    if (subLine.match(/\s$/) && !(ignoreEmptyLines && l && subLine.match(/^\s*$/))) {
+                        errors.assert.emit('error', {
+                            message: 'Illegal trailing whitespace',
+                            line: i + l,
+                            column: subLine.length,
+                            fixed: true
+                        });
+
+                        subLines[l] = subLine.replace(/\s+$/, '');
+                    }
+                }
+                token.value = subLines.join(file.getLineBreakStyle());
+            } else if (token.type === 'EOF') {
+                // non new line eof
+                checkTokenWhiteSpace(token);
+            }
+
+            lastLine = i;
+        }
+    }
 };

presets/mdcs.json

@@ -28,5 +28,6 @@
         "beforeConsequent": true,
         "afterConsequent": true,
         "beforeAlternate": true
-    }
+    },
+    "disallowTrailingWhitespace": true
 }

test/specs/rules/disallow-trailing-whitespace.js

@@ -1,5 +1,6 @@
 var Checker = require('../../../lib/checker');
 var assert = require('assert');
+var reportAndFix = require('../../lib/assertHelpers').reportAndFix;
 
 describe('rules/disallow-trailing-whitespace', function() {
     var checker;
@@ -37,6 +38,22 @@ describe('rules/disallow-trailing-whitespace', function() {
         it('should not report when there is no trailing whitespace', function() {
             assert(checker.checkString('var x;').isEmpty());
         });
+
+        it('should report when there is trailing whitespace in line comment', function() {
+            assert(checker.checkString('// x \n').getErrorCount() === 1);
+        });
+
+        it('should report when there is trailing whitespace in block comment', function() {
+            assert(checker.checkString('/*\n *\n \t\n */').getErrorCount() === 1);
+        });
+
+        it('should not report trailing spaces the last line of block comment', function() {
+            assert(checker.checkString('/*\n\n */').isEmpty());
+        });
+
+        it('should report trailing whitespace on the first empty line', function() {
+            assert(checker.checkString('\t\n// eof').getErrorCount() === 1);
+        });
     });
 
     describe('ignoreEmptyLines', function() {
@@ -47,6 +64,48 @@ describe('rules/disallow-trailing-whitespace', function() {
         it('should not report trailing whitespace on empty lines', function() {
             assert(checker.checkString('if(a){\n\tb=c;\n\t\n}').isEmpty());
         });
+
+        it('should not report trailing whitespace on empty lines in block comments', function() {
+            assert(checker.checkString('/*\n *\n \t\n */').isEmpty());
+        });
+
+        it('should not report trailing whitespace on the first empty line', function() {
+            assert(checker.checkString('\t\n//').isEmpty());
+        });
+    });
+
+    reportAndFix({
+        name: 'should fix trailing space (simple case)',
+        rules: { disallowTrailingWhitespace: true },
+        input: 'var x; ',
+        output: 'var x;'
+    });
+
+    reportAndFix({
+        name: 'should fix trailing space in line comments',
+        rules: { disallowTrailingWhitespace: true },
+        input: '// bla \n',
+        output: '// bla\n'
     });
 
+    reportAndFix({
+        name: 'should fix trailing space in block comments',
+        rules: { disallowTrailingWhitespace: true },
+        input: '/*\nbla\n\t\n*/',
+        output: '/*\nbla\n\n*/'
+    });
+
+    reportAndFix({
+        name: 'should ignore empty lines',
+        rules: { disallowTrailingWhitespace: 'ignoreEmptyLines' },
+        input: 'var x; \n\t\n',
+        output: 'var x;\n\t\n'
+    });
+
+    reportAndFix({
+        name: 'should ignore empty lines in block comments',
+        rules: { disallowTrailingWhitespace: 'ignoreEmptyLines' },
+        input: '/* \nbla\n\t\n*/',
+        output: '/*\nbla\n\t\n*/'
+    });
 });