pubst - npm Package Compare versions

Comparing version 0.3.0 to 0.4.0

CHANGELOG.md

@@ -0,1 +1,7 @@
+## v0.4.0 - Sep 21 2018
+  + Adds `validator` option to topic configuration.
+
+## v0.3.0 - Sep 11 2018
+  + Adds topic configuration
+
 ## v0.2.1 - Apr 27 2018
@@ -2,0 +8,0 @@ + Adds documentation

lib/pubst.js

@@ -100,3 +100,6 @@ 'use strict';
     doPrime: true,
-    allowRepeats: false
+    allowRepeats: false,
+    validator: function validator() {
+      return { valid: true, messages: [] };
+    }
   };
@@ -122,2 +125,14 @@
 
+  function buildValidationErrorMessage(topicName, validationMessages, payload) {
+    var messages = '';
+    if (Array.isArray(validationMessages) && validationMessages.length > 0) {
+      var s = validationMessages.length === 1 ? '' : 's';
+      messages = 'Message' + s + ':\n  ' + validationMessages.join('\n  ');
+    }
+
+    var payloadString = 'Received Payload:\n  ' + JSON.stringify(payload, null, 2);
+
+    return 'Validation failed for topic \'' + topicName + '\'.\n ' + messages + '\n ' + payloadString;
+  }
+
   /**
@@ -152,2 +167,14 @@ * @summary Configure a new topic.
    *    </li>
+   *    <li>
+   *      `validator` - Validation function to assert that published values are valid before sent to subscribers.
+   *      Function will be called with each published payload.
+   *      If a payload fails validation, an error will be thrown during the `publish` call.
+   *      The function should return something like:<br/>
+   *      <code>
+   *        {
+   *          valid: false,
+   *          messages: ['Message 1', 'Message 2']
+   *        }
+   *      </code>
+   *    </li>
    *  </ul>
@@ -167,2 +194,9 @@ * </p>
 
+    if (isDefined(topic.default)) {
+      var defaultValidationResult = topic.validator(topic.default);
+      if (!defaultValidationResult.valid) {
+        warn('\'' + topic.name + '\' has been configured with a default value that does not pass validation.\nComplete message:\n' + buildValidationErrorMessage(topic.name, defaultValidationResult.messages, topic.default));
+      }
+    }
+
     topics[topic.name] = topic;
@@ -288,2 +322,13 @@ }
 
+    var topicConfig = getTopicConfig(topic);
+
+    if (!topicConfig.eventOnly) {
+      var validationResult = topicConfig.validator(payload);
+
+      if (!validationResult || !validationResult.valid) {
+        var messages = validationResult ? validationResult.messages : [];
+        throw new Error(buildValidationErrorMessage(topic, messages, payload));
+      }
+    }
+
     store[topic] = payload;
@@ -290,0 +335,0 @@ var subs = allSubsFor(topic);

package.json

 {
   "name": "pubst",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "A slightly opinionated pub/sub event emitter for JavaScript.",
@@ -41,3 +41,3 @@ "main": "lib/pubst.js",
     "clear-require": "2.0.0",
-    "eslint": "5.5.0",
+    "eslint": "5.6.0",
     "jsdoc": "3.5.5",
@@ -47,5 +47,5 @@ "mocha": "5.2.0",
     "shx": "0.3.2",
-    "sinon": "6.2.0",
+    "sinon": "6.3.4",
     "sinon-chai": "3.2.0"
   }
 }

README.md

@@ -114,2 +114,3 @@ # Pubst
     + This can be overridden by subscribers.
+  + `validator` - A validation function to assert that published values are valid before they are sent to subscribers.
 
@@ -123,3 +124,18 @@ #### Examples
     default: false,
-    doPrime: true
+    doPrime: true,
+    validator: payload => {
+      const valid = typeof payload === 'boolean';
+      if (!valid) {
+        return {
+          valid,
+          messages: [
+            'Value must be a boolean'
+          ]
+        };
+      }
+
+      return {
+        valid
+      };
+    }
   },
@@ -130,3 +146,6 @@ {
     allowRepeats: true,
-    doPrime: false
+    doPrime: false,
+    validator: payload => ({
+      valid: typeof payload === 'number'
+    })
   },
@@ -133,0 +152,0 @@ {

src/pubst.js

@@ -88,3 +88,4 @@ /**
     doPrime: true,
-    allowRepeats: false
+    allowRepeats: false,
+    validator: () => ({valid: true, messages: []})
   };
@@ -116,2 +117,14 @@
 
+  function buildValidationErrorMessage(topicName, validationMessages, payload) {
+    let messages = '';
+    if (Array.isArray(validationMessages) && validationMessages.length > 0) {
+      const s = validationMessages.length === 1 ? '' : 's';
+      messages = `Message${s}:\n  ${validationMessages.join('\n  ')}`;
+    }
+
+    const payloadString = 'Received Payload:\n  ' + JSON.stringify(payload, null, 2);
+
+    return `Validation failed for topic '${topicName}'.\n ${messages}\n ${payloadString}`;
+  }
+
   /**
@@ -146,2 +159,14 @@ * @summary Configure a new topic.
    *    </li>
+   *    <li>
+   *      `validator` - Validation function to assert that published values are valid before sent to subscribers.
+   *      Function will be called with each published payload.
+   *      If a payload fails validation, an error will be thrown during the `publish` call.
+   *      The function should return something like:<br/>
+   *      <code>
+   *        {
+   *          valid: false,
+   *          messages: ['Message 1', 'Message 2']
+   *        }
+   *      </code>
+   *    </li>
    *  </ul>
@@ -161,2 +186,11 @@ * </p>
 
+    if (isDefined(topic.default)) {
+      const defaultValidationResult = topic.validator(topic.default);
+      if (!defaultValidationResult.valid) {
+        warn(`'${topic.name}' has been configured with a default value that does not pass validation.
+Complete message:
+${buildValidationErrorMessage(topic.name, defaultValidationResult.messages, topic.default)}`);
+      }
+    }
+
     topics[topic.name] = topic;
@@ -275,2 +309,13 @@
 
+    const topicConfig = getTopicConfig(topic);
+
+    if (!topicConfig.eventOnly) {
+      const validationResult = topicConfig.validator(payload);
+
+      if (!validationResult || !validationResult.valid) {
+        const messages = validationResult ? validationResult.messages : [];
+        throw new Error(buildValidationErrorMessage(topic, messages, payload));
+      }
+    }
+
     store[topic] = payload;
@@ -277,0 +322,0 @@ const subs = allSubsFor(topic);

src/pubst.test.js

@@ -532,5 +532,97 @@ const clearRequire = require('clear-require');
     });
+
+    describe('validator', () => {
+      it('allows all values by default', () => {
+        pubst.addTopics([
+          {
+            name: TEST_TOPIC_1,
+            doPrime: false
+          }
+        ]);
+
+        const handler1 = sinon.spy();
+
+        pubst.subscribe(TEST_TOPIC_1, handler1);
+
+        pubst.publish(TEST_TOPIC_1, 'Hello');
+        pubst.publish(TEST_TOPIC_1, 12);
+
+        clock.tick(1);
+
+        expect(handler1).to.have.been.calledWith('Hello', TEST_TOPIC_1);
+        expect(handler1).to.have.been.calledWith(12, TEST_TOPIC_1);
+      });
+
+      it('fails when valid is false', () => {
+        pubst.addTopic({
+          name: TEST_TOPIC_1,
+          doPrime: false,
+          validator: () => ({valid: false, messages: ['message 1', 'message 2']})
+        });
+
+        const handler1 = sinon.spy();
+
+        pubst.subscribe(TEST_TOPIC_1, handler1);
+
+        try {
+          pubst.publish(TEST_TOPIC_1, 'Hello');
+          throw new Error('This publish should have thrown');
+        } catch (e) {
+          const {message} = e;
+          expect(message).to.contain('message 1');
+          expect(message).to.contain('message 2');
+          expect(message).to.contain(TEST_TOPIC_1);
+          expect(message).to.contain('Hello');
+        }
+
+        clock.tick(1);
+
+        expect(handler1).not.to.have.been.called;
+      });
+
+      it('fails when result is falsey', () => {
+        pubst.addTopic({
+          name: TEST_TOPIC_1,
+          doPrime: false,
+          validator: () => false
+        });
+
+        const handler1 = sinon.spy();
+
+        pubst.subscribe(TEST_TOPIC_1, handler1);
+
+        try {
+          pubst.publish(TEST_TOPIC_1, 'Hello');
+          throw new Error('This publish should have thrown');
+        } catch (e) {
+          const {message} = e;
+          expect(message).to.contain(TEST_TOPIC_1);
+          expect(message).to.contain('Hello');
+        }
+
+        clock.tick(1);
+
+        expect(handler1).not.to.have.been.called;
+      });
+
+      it('allows payloads when valid is true', () => {
+        pubst.addTopic({
+          name: TEST_TOPIC_1,
+          doPrime: false,
+          validator: () => ({valid: true})
+        });
+
+        const handler1 = sinon.spy();
+
+        pubst.subscribe(TEST_TOPIC_1, handler1);
+
+        pubst.publish(TEST_TOPIC_1, 'Hello');
+
+        clock.tick(1);
+
+        expect(handler1).to.have.been.calledOnceWith('Hello', TEST_TOPIC_1);
+      });
+    });
   });
 
-
   describe('publish & subscribe', () => {
@@ -537,0 +629,0 @@ it('calls the subscriber if the topic already has a set value', () => {

No alert changes

Improved metrics

Total package byte prevSize

85157

increased by8.52%

Lines of code

1682

increased by9.43%

Number of lines in readme file

287

increased by7.09%

No dependency changes