traceback-safe/lib/v8.js

Easy access to the call stack, written in pure JavaScript

// Taken from Node source, deps/v8/src/messages.js
//
// node: 0.6.2
// v8: 3.6.6.8

exports.FormatStackTrace = FormatStackTrace;

function FormatStackTrace(error, frames) {
  var lines = [];
  try {
    lines.push(error.toString());
  } catch (e) {
    try {
      lines.push("<error: " + e + ">");
    } catch (ee) {
      lines.push("<error>");
    }
  }
  for (var i = 0; i < frames.length; i++) {
    var frame = frames[i];
    var line;
    try {
      line = FormatSourcePosition(frame);
    } catch (e) {
      try {
        line = "<error: " + e + ">";
      } catch (ee) {
        // Any code that reaches this point is seriously nasty!
        line = "<error>";
      }
    }
    lines.push("    at " + line);
  }
  return lines.join("\n");
}

function FormatSourcePosition(frame) {
  var fileName;
  var fileLocation = "";
  if (frame.isNative()) {
    fileLocation = "native";
  } else if (frame.isEval()) {
    fileName = frame.getScriptNameOrSourceURL();
    if (!fileName)
      fileLocation = frame.getEvalOrigin();
  } else {
    fileName = frame.getFileName();
  }

  if (fileName) {
    fileLocation += fileName;
    var lineNumber = frame.getLineNumber();
    if (lineNumber != null) {
      fileLocation += ":" + lineNumber;
      var columnNumber = frame.getColumnNumber();
      if (columnNumber) {
        fileLocation += ":" + columnNumber;
      }
    }
  }

  if (!fileLocation) {
    fileLocation = "unknown source";
  }
  var line = "";
  var functionName = frame.getFunction().name;
  var addPrefix = true;
  var isConstructor = frame.isConstructor();
  var isMethodCall = !(frame.isToplevel() || isConstructor);
  if (isMethodCall) {
    var methodName = frame.getMethodName();
    line += frame.getTypeName() + ".";
    if (functionName) {
      line += functionName;
      if (methodName && (methodName != functionName)) {
        line += " [as " + methodName + "]";
      }
    } else {
      line += methodName || "<anonymous>";
    }
  } else if (isConstructor) {
    line += "new " + (functionName || "<anonymous>");
  } else if (functionName) {
    line += functionName;
  } else {
    line += fileLocation;
    addPrefix = false;
  }
  if (addPrefix) {
    line += " (" + fileLocation + ")";
  }
  return line;
}