feat: export HttpError from http-errors library

Author: Micheal Hill

lib/application.js

@@ -21,6 +21,7 @@ const http = require('http');
 const only = require('only');
 const convert = require('koa-convert');
 const deprecate = require('depd')('koa');
+const { HttpError } = require('http-errors');
 
 /**
  * Expose `Application` class.
@@ -257,3 +258,9 @@ function respond(ctx) {
   }
   res.end(body);
 }
+
+/**
+ * Make HttpError available to consumers of the library so that consumers don't
+ * have a direct dependency upon `http-errors`
+ */
+module.exports.HttpError = HttpError;

test/application/index.js

@@ -77,4 +77,12 @@ describe('app', () => {
     const app = new Koa({ subdomainOffset });
     assert.strictEqual(app.subdomainOffset, subdomainOffset);
   });
+
+  it('should have a static property exporting `HttpError` from http-errors library', () => {
+    const CreateError = require('http-errors');
+
+    assert.notEqual(Koa.HttpError, undefined);
+    assert.deepStrictEqual(Koa.HttpError, CreateError.HttpError);
+    assert.throws(() => { throw new CreateError(500, 'test error'); }, Koa.HttpError);
+  });
 });