Merge pull request #37 from parcel-bundler/column-offset-bugfix

Fix bug with column offset

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@parcel/source-map",
-  "version": "2.0.0-alpha.4.16",
+  "version": "2.0.0-alpha.4.17",
   "main": "./dist/node.js",
   "browser": "./dist/wasm-browser.js",
   "license": "MIT",

src/MappingContainer.cpp

@@ -507,6 +507,10 @@ void MappingContainer::addIndexedMapping(int generatedLine, int generatedColumn,
 
 // TODO: This can be improved performance wise, by not having line stored in both MappingLine and Mapping
 void MappingContainer::offsetLines(int line, int lineOffset) {
+    if (_generated_lines < line) {
+        return;
+    }
+
     int lineCount = this->_mapping_lines.size();
 
     if (lineOffset > 0) {
@@ -537,6 +541,10 @@ void MappingContainer::offsetLines(int line, int lineOffset) {
 }
 
 void MappingContainer::offsetColumns(int line, int column, int columnOffset) {
+    if (_generated_lines < line) {
+        return;
+    }
+
     auto mappingsCount = this->_mapping_lines[line]._segments.size();
     for (int i = 0; i < mappingsCount; ++i) {
         if (this->_mapping_lines[line]._segments[i].generated.column < column) {

test/offset-utils.test.js

@@ -87,6 +87,20 @@ describe('SourceMap - Offset Utils', () => {
     });
   });
 
+  it('Column offset empty map', () => {
+    let map = new SourceMap('/');
+
+    map.offsetColumns(1, 0, 2);
+    map.offsetColumns(2, 15, -4);
+
+    assert.deepEqual(map.getMap(), {
+      sources: [],
+      sourcesContent: [],
+      names: [],
+      mappings: [],
+    });
+  });
+
   it('Positive line offset', () => {
     let map = new SourceMap('/test-root');
 
@@ -236,4 +250,18 @@ describe('SourceMap - Offset Utils', () => {
       ],
     });
   });
+
+  it('Line offset empty map', () => {
+    let map = new SourceMap('/');
+
+    map.offsetLines(1, 2);
+    map.offsetLines(2, 5);
+
+    assert.deepEqual(map.getMap(), {
+      sources: [],
+      sourcesContent: [],
+      names: [],
+      mappings: [],
+    });
+  });
 });