fix: function name should be obtained from next frams’s position

Author: JLHwung

source-map-support.js

@@ -335,8 +335,13 @@ function cloneCallSite(frame) {
   return object;
 }
 
-function wrapCallSite(frame) {
+function wrapCallSite(frame, state) {
+  // provides interface backward compatibility
+  if (state === undefined) {
+    state = { nextPosition: null, curPosition: null }
+  }
   if(frame.isNative()) {
+    state.curPosition = null;
     return frame;
   }
 
@@ -360,9 +365,15 @@ function wrapCallSite(frame) {
       line: line,
       column: column
     });
+    state.curPosition = position;
     frame = cloneCallSite(frame);
     var originalFunctionName = frame.getFunctionName;
-    frame.getFunctionName = function() { return position.name || originalFunctionName(); };
+    frame.getFunctionName = function() {
+      if (state.nextPosition === null) {
+        return originalFunctionName();
+      }
+      return state.nextPosition.name || originalFunctionName();
+    };
     frame.getFileName = function() { return position.source; };
     frame.getLineNumber = function() { return position.line; };
     frame.getColumnNumber = function() { return position.column + 1; };
@@ -395,9 +406,14 @@ function prepareStackTrace(error, stack) {
   var message = error.message || '';
   var errorString = name + ": " + message;
 
-  return errorString + stack.map(function(frame) {
-    return '\n    at ' + wrapCallSite(frame);
-  }).join('');
+  var state = { nextPosition: null, curPosition: null };
+  var processedStack = [];
+  for (var i = stack.length - 1; i >= 0; i--) {
+    processedStack.push('\n    at ' + wrapCallSite(stack[i], state));
+    state.nextPosition = state.curPosition;
+  }
+  state.curPosition = state.nextPosition = null;
+  return errorString + processedStack.reverse().join('');
 }
 
 // Generate position and snippet of original source with pointer
@@ -561,7 +577,7 @@ exports.resetRetrieveHandlers = function() {
 
   retrieveFileHandlers = originalRetrieveFileHandlers.slice(0);
   retrieveMapHandlers = originalRetrieveMapHandlers.slice(0);
-  
+
   retrieveSourceMap = handlerExec(retrieveMapHandlers);
   retrieveFile = handlerExec(retrieveFileHandlers);
 }

test.js

@@ -331,7 +331,12 @@ it('maps original name from source', function() {
     generated: { line: 2, column: 8 },
     original: { line: 1000, column: 10 },
     source: '.original.js',
-    name: 'myOriginalName'
+  });
+  sourceMap.addMapping({
+    generated: { line: 4, column: 0 },
+    original: { line: 1002, column: 1 },
+    source: ".original.js",
+    name: "myOriginalName"
   });
   compareStackTrace(sourceMap, [
     'function foo() {',
@@ -341,7 +346,7 @@ it('maps original name from source', function() {
   ], [
     'Error: test',
     /^    at myOriginalName \((?:.*[/\\])?\.original.js:1000:11\)$/,
-    /^    at Object\.exports\.test \((?:.*[/\\])?\.generated.js:4:1\)$/
+    /^    at Object\.exports\.test \((?:.*[/\\])?\.original.js:1002:2\)$/
   ]);
 });