Merge pull request #19 from codebien/fix-zero-mappings

Exclude empty mappings

Author: vmihailenco

consumer.go

@@ -195,6 +195,10 @@ func (c *Consumer) source(
 var match *mapping
 // Mapping not found
 if i == len(m.mappings) {
+// Empty mappings
+if len(m.mappings) == 0 {
+return
+}
 // lets see if the line is correct but the column is bigger
 match = &m.mappings[i-1]
 if int(match.genLine) != genLine {

consumer_test.go

@@ -66,6 +66,23 @@ func (test *sourceMapTest) assert(t *testing.T, smap *sourcemap.Consumer) {
 }
 }
 
+func TestSourceWithEmptySourceMap(t *testing.T) {
+var jsmap = `{
+ "version": 3,
+ "mappings": ";;"
+}`
+
+smap, err := sourcemap.Parse("noname", []byte(jsmap))
+if err != nil {
+t.Fatal(err)
+}
+
+_, _, _, _, matched := smap.Source(1, 1)
+if matched {
+t.Error("it is unexpected to match an empty SourceMap")
+}
+}
+
 func TestSourceMap(t *testing.T) {
 testSourceMap(t, sourceMapJSON)
 }