Add optional statusCode parameter to Boom.isBoom, resolves #265 (#266)

API.md

@@ -67,10 +67,16 @@ var error = new Error('Unexpected input');
 Boom.boomify(error, { statusCode: 400 });
 ```
 
-##### `isBoom(err)`
+##### `isBoom(err, statusCode)`
 
-Identifies whether an error is a `Boom` object. Same as calling `instanceof Boom`.
+Identifies whether an error is a `Boom` object. Same as calling `instanceof Boom`. 
+- `err` - Error object.
+- `statusCode` - optional status code.
 
+```js
+Boom.isBoom(Boom.badRequest()); // true
+Boom.isBoom(Boom.badRequest(), 400); // true
+```
 #### HTTP 4xx Errors
 
 ##### `Boom.badRequest([message], [data])`

lib/index.d.ts

@@ -130,10 +130,11 @@ export interface Output {
 * Specifies if an error object is a valid boom object
 *
 * @param err - The error object
+* @param statusCode - Optional status code
 *
-* @returns Returns a boolean stating if the error object is a valid boom object
+* @returns Returns a boolean stating if the error object is a valid boom object and it has the provided statusCode (if present)
 */
-export function isBoom(err: Error): err is Boom;
+export function isBoom(err: Error, statusCode?: number): err is Boom;
 
 
 /**

lib/index.js

@@ -96,9 +96,9 @@ exports.Boom = class extends Error {
 };
 
 
-exports.isBoom = function (err) {
+exports.isBoom = function (err, statusCode) {
 
-    return err instanceof Error && !!err.isBoom;
+    return err instanceof Error && !!err.isBoom && (statusCode ? err.output.statusCode === statusCode : true);
 };
 
 

test/index.js

@@ -145,6 +145,16 @@ describe('Boom', () => {
             expect(Boom.isBoom({ isBoom: true })).to.be.false();
             expect(Boom.isBoom(null)).to.be.false();
         });
+
+        it('returns true for valid boom object and valid status code', () => {
+
+            expect(Boom.isBoom(Boom.notFound(),404)).to.be.true();
+        });
+
+        it('returns false for valid boom object and wrong status code', () => {
+
+            expect(Boom.isBoom(Boom.notFound(),503)).to.be.false();
+        });
     });
 
     describe('boomify()', () => {