Export a helper function that supports creating instances by status c…

…ode with a fallback to an Unknown class.

README.md

@@ -18,6 +18,9 @@ Usage
 
     var httpErrors = require('httperrors');
 
+    // Instatiate by status code:
+    var myError = httpErrors(412);
+
     // Instantiate by name (UpperCamelCase):
     var err = new httpErrors.NotFound('The thing you were looking for was not found');
 

lib/httpErrors.js

@@ -42,7 +42,17 @@ var httpErrorNameByStatusCode = {
     511: 'Network Authentication Required' // RFC 6585
 };
 
-var httpErrors = module.exports = {};
+var httpErrors = module.exports = function (options) {
+    if (typeof options === 'undefined') {
+        options = {};
+    } else if (typeof options === 'number') {
+        options = {statusCode: options};
+    }
+    options.status = options.statusCode;
+    return (httpErrors[options.statusCode] || httpErrors.Unknown)(options);
+};
+
+httpErrors.Unknown = createError({name: 'Unknown'});
 
 /// Map the error codes/names, as defined in Node's [http
 /// module](http://nodejs.org/docs/latest/api/http.html).

test/httpErrors.js

@@ -41,4 +41,30 @@ describe('httpErrors', function () {
         expect(err.message, 'to equal', 'foo');
         expect(err.url, 'to equal', 'bar');
     });
+
+    describe('when invoked as a function', function () {
+        it('should create an instance of httpErrors.Unknown if called with no arguments', function () {
+            expect(httpErrors().name, 'to equal', 'Unknown');
+        });
+
+        describe('and passed a number', function () {
+            it('should create an instance of the proper error for a known status code', function () {
+                expect(httpErrors(412).name, 'to equal', 'PreconditionFailed');
+            });
+
+            it('should create an instance of httpErrors.Unknown if given a status code that is not directly supported', function () {
+                expect(httpErrors(595).name, 'to equal', 'Unknown');
+            });
+        });
+
+        describe('and passed an options object', function () {
+            it('should create an instance of httpErrors.Unknown if the status code is not directly supported', function () {
+                expect(httpErrors({statusCode: 595}).name, 'to equal', 'Unknown');
+            });
+
+            it('should create an instance of httpErrors.Unknown if no status code is provided', function () {
+                expect(httpErrors({foo: 'bar'}).name, 'to equal', 'Unknown');
+            });
+        });
+    });
 });