Fix pipes and testcases

lib/utils/pipes.js

@@ -1,7 +1,8 @@
 'use strict';
 
-import {Pipe, InvalidPipeArgumentException} from 'angular2/core';
+import {Pipe} from 'angular2/core';
-import {isString} from 'angular2/src/facade/lang';
+import {isString, stringify, isBlank} from 'angular2/src/facade/lang';
+import {BaseException} from 'angular2/src/facade/exceptions';
 import {JsonPointer} from './JsonPointer';
 import marked from 'marked';
 
@@ -15,20 +16,27 @@ marked.setOptions({
   smartypants: false
 });
 
+class InvalidPipeArgumentException extends BaseException {
+  constructor(type, value) {
+    super(`Invalid argument '${value}' for pipe '${stringify(type)}'`);
+  }
+}
 
 @Pipe({ name: 'keys' })
 export class KeysPipe {
-  transform(obj) {
+  transform(value) {
-    if (typeof obj !== 'object') {
+    if (isBlank(value)) return value;
-      throw new InvalidPipeArgumentException(ValuesPipe, obj);
+    if (typeof value !== 'object') {
+      throw new InvalidPipeArgumentException(ValuesPipe, value);
     }
-    return Object.keys(obj);
+    return Object.keys(value);
   }
 }
 
 @Pipe({ name: 'values' })
 export class ValuesPipe {
   transform(value) {
+    if (isBlank(value)) return value;
     if (typeof value !== 'object') {
       throw new InvalidPipeArgumentException(ValuesPipe, value);
     }
@@ -39,6 +47,7 @@ export class ValuesPipe {
 @Pipe({ name: 'jsonPointerEscape' })
 export class JsonPointerEscapePipe {
   transform(value) {
+    if (isBlank(value)) return value;
     if (!isString(value)) {
       throw new InvalidPipeArgumentException(JsonPointerEscapePipe, value);
     }
@@ -49,6 +58,7 @@ export class JsonPointerEscapePipe {
 @Pipe({ name: 'marked' })
 export class MarkedPipe {
   transform(value) {
+    if (isBlank(value)) return value;
     if (!isString(value)) {
       throw new InvalidPipeArgumentException(JsonPointerEscapePipe, value);
     }

tests/unit/pipes.spec.js

@@ -24,7 +24,11 @@ describe('KeysPipe and ValuesPipe', () => {
 
     it('should not support other objects', () => {
       (() => keysPipe.transform(45)).should.throw();
-      (() => keysPipe.transform(null)).should.throw();
+      (() => keysPipe.transform('45')).should.throw();
+    });
+
+    it('should not throw on blank input', () => {
+      (() => valuesPipe.transform()).should.not.throw();
     });
   });
 
@@ -36,7 +40,11 @@ describe('KeysPipe and ValuesPipe', () => {
 
     it('should not support other objects', () => {
       (() => valuesPipe.transform(45)).should.throw();
-      (() => valuesPipe.transform(null)).should.throw();
+      (() => valuesPipe.transform('45')).should.throw();
+    });
+
+    it('should not throw on blank input', () => {
+      (() => keysPipe.transform()).should.not.throw();
     });
   });
 });
@@ -52,7 +60,7 @@ describe('JsonPointerEscapePipe', () => {
     pipe = new JsonPointerEscapePipe();
   });
 
-  describe('KeysPipe transform', () => {
+  describe('JsonPointerEscapePipe transform', () => {
     it('should escpae pointer', () => {
       var val = pipe.transform(unescaped);
       val.should.be.equal(escaped);
@@ -62,6 +70,10 @@ describe('JsonPointerEscapePipe', () => {
       (() => pipe.transform(45)).should.throw();
       (() => pipe.transform({})).should.throw();
     });
+
+    it('should not throw on blank input', () => {
+      (() => pipe.transform()).should.not.throw();
+    });
   });
 });
 
@@ -76,7 +88,7 @@ describe('MarkedPipe', () => {
     pipe = new MarkedPipe();
   });
 
-  describe('KeysPipe transform', () => {
+  describe('MarkedPipe transform', () => {
     it('should escpae pointer', () => {
       var val = pipe.transform(unmarked);
       val.should.be.equal(marked);
@@ -86,5 +98,9 @@ describe('MarkedPipe', () => {
       (() => pipe.transform(45)).should.throw();
       (() => pipe.transform({})).should.throw();
     });
+
+    it('should not throw on blank input', () => {
+      (() => pipe.transform()).should.not.throw();
+    });
   });
 });