revised stderr message handling

README.md

@@ -42,13 +42,13 @@ nodeCleanup(function (exitCode, signal) {
 If you only want to install your own messages for *Ctrl-C* and uncaught exception (either or both), you can do this:
 
 ```js
-nodeCleanup(null, {
+nodeCleanup({
     ctrl_C: "{^C}",
     uncaughtException: "Uh oh. Look what happened:"
 });
 ```
 
-To get just the default `stderr` messages, without installing a cleanup handler:
+To get the default `stderr` messages, without installing a cleanup handler:
 
 ```js
 nodeCleanup();
@@ -104,19 +104,22 @@ nodeCleanup(function (exitCode, signal) {
 
 ### `nodeCleanup()`
 
-`nodeCleanup()` has the following ([FlowType](https://flowtype.org/docs/getting-started.html#_)) signature:
+`nodeCleanup()` has the following available ([FlowType](https://flowtype.org/docs/getting-started.html#_)) signatures:
 
 ```js
-function nodeCleanup(cleanupHandler?: Function, messages?: object): void
+function nodeCleanup(cleanupHandler: Function): void
+function nodeCleanup(cleanupHandler: Function, stderrMessages: object): void
+function nodeCleanup(stderrMessages: object): void
+function nodeCleanup(): void
 ```
 
-`nodeCleanup()` installs a cleanup handler. It may also assign messages to write to `stderr` on SIGINT or an uncaught exception. Both parameters are optional. If not `cleanupHandler` is provided, the `stderr` messages are still written. If no `messages` are provided, default `stderr` messages are written. Calling `nodeCleanup()` with no parameters just installs these default messages.
+The 1st form installs a cleanup handler. The 2nd form also assigns messages to write to `stderr` on SIGINT or an uncaught exception. The 3rd and 4th forms only assign messages to write to `stderr`, without installing a cleanup handler. The 4th form assigns default `stderr` messages.
 
-`cleanupHandler` is a cleanup handler callback and is described in its own section below. When null or undefined, termination events all result in the process terminating, including signals.
+`cleanupHandler` is a cleanup handler callback and is described in its own section below. When no cleanup handlers are installed, termination events all result in the process terminating, including signal events.
 
-`messages` is an object mapping any of the keys `ctrl_C` and `uncaughtException` to message strings that output to `stderr`. Default messages are provided for omitted messages. Set a message to the empty string `''` inhibit the message.
+`stderrMessages` is an object mapping any of the keys `ctrl_C` and `uncaughtException` to message strings that output to `stderr`. Set a message to the empty string `''` inhibit a previously-assigned message.
 
-`nodeCleanup()` may be called multiple times to install multiple cleanup handlers. Each of these handlers runs for each signal or termination condition. The first call to `nodeCleanup()` establishes the `stderr` messages; messages passed to subsequent calls are ignored.
+`nodeCleanup()` may be called multiple times to install multiple cleanup handlers or override previous messages. Each handler gets called on each signal or termination condition. The most recently assigned messages apply.
 
 ### `nodeCleanup.uninstall()`
 
@@ -162,12 +165,11 @@ subtap
 
 ## Incompatibilities with v1.0.x
 
-TBD
+`node-cleanup` v2+ is not fully compatible with v1.x. You may need to change your usage to upgrade. These are the potential incompatibilities:
 
-- default messages
-- catches SIGHUP, SIGQUIT, and SIGTERM
+- The cleanup handlers now also run on SIGHUP, SIGQUIT, and SIGTERM, which were not getting cleanup processing before.
+- `stderr` messages are handled quite differently. Previously, there were defaults that you had to override, and only your first message assignments applied. Now, the defaults **only** install with the parameterless call `nodeCleanup()`. Otherwise there are no messages unless you provide them. Moreover, the most recent message assignments are the ones that get used.
 
 ## Credit
 
 This module began by borrowing and modifying code from CanyonCasa's [answer to a stackoverflow question](http://stackoverflow.com/a/21947851/650894). I had found the code necessary for all my node projects. @Banjocat piped in with a [comment](http://stackoverflow.com/questions/14031763/doing-a-cleanup-action-just-before-node-js-exits/21947851#comment68567869_21947851) about how the solution didn't properly handle SIGINT. (See [this detailed explanation](https://www.cons.org/cracauer/sigint.html) of the SIGINT problem). I have completely rewritten the module to properly deal with SIGINT and other signals (I hope!). The rewrite also provides some additional flexibility that @zixia and I found ourselves needing for our respective projects.
-

node-cleanup.js

@@ -12,9 +12,17 @@ The process terminates after cleanup, except possibly on signals. If any cleanup
 Install a cleanup handler as follows:
 
     var nodeCleanup = require('node-cleanup');
-    nodeCleanup(cleanupHandler, terminationMessages);
+    nodeCleanup(cleanupHandler, stderrMessages);
+    
+Or to only install stderr messages:
+
+    nodeCleanup(stderrMessages);
+
+Or to install the default stderr messages:
 
-nodeCleanup() may be called multiple times to install multiple cleanup handlers. However, only the termination messages established by the first call get used.
+    nodeCleanup();
+
+nodeCleanup() may be called multiple times to install multiple cleanup handlers. However, only the most recently installed stderr messages get used. The messages available are ctrl_C and uncaughtException.
 
 The following uninstalls all cleanup handlers and may be called multiple times in succession:
 
@@ -25,13 +33,15 @@ This module has its origin in code by  @CanyonCasa at  http://stackoverflow.com/
 
 //// CONSTANTS ////////////////////////////////////////////////////////////////
 
-var DEFAULT_SIGINT_MSG =  '[ctrl-C]';
-var DEFAULT_EXCEPTION_MSG = 'Uncaught exception...';
+var DEFAULT_MESSAGES = {
+    ctrl_C: '[ctrl-C]',
+    uncaughtException: 'Uncaught exception...'
+};
 
 //// CONFIGURATION ////////////////////////////////////////////////////////////
 
 var cleanupHandlers = null; // array of cleanup handlers to call
-var exceptionMessage = null; // stderr message for uncaught exceptions
+var messages = null; // messages to write to stderr
 
 var sigintHandler; // POSIX signal handlers
 var sighupHandler;
@@ -40,16 +50,16 @@ var sigtermHandler;
 
 //// HANDLERS /////////////////////////////////////////////////////////////////
 
-function signalHandler(signal, message)
+function signalHandler(signal)
 {
     var exit = true;
     cleanupHandlers.forEach(function (cleanup) {
         if (cleanup(null, signal) === false)
             exit = false;
     });
     if (exit) {
-        if (message !== '')
-            process.stderr.write(message + "\n");
+        if (signal === 'SIGINT' && messages && messages.ctrl_C !== '')
+            process.stderr.write(messages.ctrl_C + "\n");
         uninstall(); // don't cleanup again
         // necessary to communicate the signal to the parent process
         process.kill(process.pid, signal);
@@ -58,8 +68,8 @@ function signalHandler(signal, message)
 
 function exceptionHandler(e)
 {
-    if (exceptionMessage !== '')
-        process.stderr.write(exceptionMessage + "\n");
+    if (messages && messages.uncaughtException !== '')
+        process.stderr.write(messages.uncaughtException + "\n");
     process.stderr.write(e.stack + "\n");
     process.exit(1); // will call exitHandler() for cleanup
 }
@@ -73,22 +83,33 @@ function exitHandler(exitCode, signal)
 
 //// MAIN /////////////////////////////////////////////////////////////////////
 
-function install(cleanupHandler, messages)
+function install(cleanupHandler, stderrMessages)
 {
+    if (cleanupHandler) {
+        if (typeof cleanupHandler === 'object') {
+            stderrMessages = cleanupHandler;
+            cleanupHandler = null;
+        }
+    }
+    else if (!stderrMessages)
+        stderrMessages = DEFAULT_MESSAGES;
+
+    if (stderrMessages) {
+        if (messages === null)
+            messages = { ctrl_C: '', uncaughtException: '' };
+        if (typeof stderrMessages.ctrl_C === 'string')
+            messages.ctrl_C = stderrMessages.ctrl_C;
+        if (typeof stderrMessages.uncaughtException === 'string')
+            messages.uncaughtException = stderrMessages.uncaughtException;
+    }
+
     if (cleanupHandlers === null) {
         cleanupHandlers = []; // establish before installing handlers
 
-        messages = messages || {};
-        if (typeof messages.ctrl_C !== 'string')
-            messages.ctrl_C = DEFAULT_SIGINT_MSG;
-        if (typeof messages.uncaughtException !== 'string')
-            messages.uncaughtException = DEFAULT_EXCEPTION_MSG;
-        exceptionMessage = messages.uncaughtException;
-
-        sigintHandler = signalHandler.bind(this, 'SIGINT', messages.ctrl_C);
-        sighupHandler = signalHandler.bind(this, 'SIGHUP', '');
-        sigquitHandler = signalHandler.bind(this, 'SIGQUIT', '');
-        sigtermHandler = signalHandler.bind(this, 'SIGTERM', '');
+        sigintHandler = signalHandler.bind(this, 'SIGINT');
+        sighupHandler = signalHandler.bind(this, 'SIGHUP');
+        sigquitHandler = signalHandler.bind(this, 'SIGQUIT');
+        sigtermHandler = signalHandler.bind(this, 'SIGTERM');
 
         process.on('SIGINT', sigintHandler);
         process.on('SIGHUP', sighupHandler);

package.json

@@ -1,10 +1,10 @@
 {
   "name": "node-cleanup",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "installs cleanup handlers that always run on exiting node",
   "main": "node-cleanup.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "tap tests/*.js"
   },
   "repository": {
     "type": "git",

tests/bin/stackable.js

@@ -5,6 +5,7 @@ Child process that installs node-cleanup for testing zero, one, or multiple (two
 
 {
     handlers; number; // 0, 1, or 2 concurrent cleanup handlers
+    messages0: object|null; // messages argument for no-cleanup call, if any
     messages1: object|null; // messages argument for 1st nodeCleanup() call
     messages2: object|null; // messages argument for 2nd nodeCleanup() call
     return1: boolean; // return value of 1st cleanup handler
@@ -47,8 +48,12 @@ function cleanup2(exitCode, signal) {
 
 //// MAIN /////////////////////////////////////////////////////////////////////
 
-if (config.handlers === 0)
-    nodeCleanup();
+if (config.handlers === 0) {
+    if (config.messages0)
+        nodeCleanup(config.messages0);
+    else
+        nodeCleanup();
+}
 else {
     nodeCleanup(cleanup1, config.messages1);
     if (config.handlers > 1)