feat(blaze-consistent-eventmap-params): Add rule

closes #12, #33

README.md

@@ -67,6 +67,7 @@ Finally, enable all of the rules that you would like to use.
     "meteor/no-session": 2,
     "meteor/no-blaze-lifecycle-assignment": 2,
     "meteor/no-zero-timeout": 2
+    "meteor/blaze-consistent-eventmap-params": 2,
   }
 }
 ```
@@ -91,6 +92,7 @@ A complete example of how to set up ESLint-plugin-Meteor in a Meteor project can
 * [no-session](docs/rules/no-session.md): Prevent usage of Session
 * [no-blaze-lifecycle-assignment](docs/rules/no-blaze-lifecycle-assignment.md): Prevent deprecated template lifecycle callback assignments
 * [no-zero-timeout](docs/rules/no-zero-timeout.md): Prevent usage of Meteor.setTimeout with zero delay
+* [blaze-consistent-eventmap-params](docs/rules/blaze-consistent-eventmap-params.md): Force consistent event handler parameters in event maps
 
 ## To Do
 

docs/rules/blaze-consistent-eventmap-params.md

@@ -0,0 +1,83 @@
+# Consistent event handler parameters (blaze-consistent-eventmap-params)
+
+Force consistent event handler parameters in [event maps](http://docs.meteor.com/#/full/eventmaps)
+
+
+## Rule Details
+
+Prevent the use of differently named parameters in event handlers to achieve more consistent code
+
+The following patterns are considered warnings:
+
+```js
+// all on the client
+Template.foo.events({
+  // 'foo' does not match 'event'
+  'submit form': function (foo) {}
+})
+
+Template.foo.events({
+  // 'bar' does not match 'templateInstance'
+  'submit form': function (event, bar) {}
+})
+
+Template.foo.events({
+  // neither 'foo' nor 'bar' are correct
+  'submit form': function (foo, bar) {}
+})
+
+```
+
+The following patterns are not warnings:
+
+```js
+// on the client
+Template.foo.events({
+  'submit form': function (event) {}
+})
+
+// on the client
+Template.foo.events({
+  'submit form': function (event, templateInstance) {}
+})
+
+```
+
+### Options
+
+You can optionally set the names of the parameters.  
+You can set the name of the event parameter using `eventParamName` and the name of the template-instance parameterusing `templateInstanceParamName`.  
+Here are examples of how to do this:
+
+```js
+/*
+ eslint meteor/blaze-consistent-eventmap-params: [2, {"eventParamName": "evt"}]
+ */
+Template.foo.events({
+  'submit form': function (evt) {}
+})
+
+/*
+ eslint meteor/blaze-consistent-eventmap-params: [2, {"templateInstanceParamName": "tmplInst"}]
+ */
+Template.foo.events({
+  'submit form': function (event, tmplInst) {}
+})
+
+/*
+ eslint meteor/blaze-consistent-eventmap-params: [2, {"eventParamName": "evt", "templateInstanceParamName": "tmplInst"}]
+ */
+Template.foo.events({
+  'submit form': function (evt, tmplInst) {}
+})
+
+```
+
+## Limitations
+
+Checks client-side only.  
+If you use an event map in a universal file (server and client) then the `Meteor.isClient` checks must happen in `if`-conditions with exactly one condition.
+
+## Further Reading
+
+* http://docs.meteor.com/#/full/eventmaps

lib/index.js

@@ -28,7 +28,8 @@ module.exports = {
     'audit-argument-checks': unpack('./rules/audit-argument-checks'),
     'no-session': unpack('./rules/no-session'),
     'no-blaze-lifecycle-assignment': unpack('./rules/no-blaze-lifecycle-assignment'),
-    'no-zero-timeout': unpack('./rules/no-zero-timeout')
+    'no-zero-timeout': unpack('./rules/no-zero-timeout'),
+    'blaze-consistent-eventmap-params': unpack('./rules/blaze-consistent-eventmap-params')
   },
   rulesConfig: {
 
@@ -46,6 +47,7 @@ module.exports = {
     'audit-argument-checks': 0,
     'no-session': 0,
     'no-blaze-lifecycle-assignment': 0,
-    'no-zero-timeout': 0
+    'no-zero-timeout': 0,
+    'blaze-consistent-eventmap-params': 0
   }
 }

lib/rules/blaze-consistent-eventmap-params.js

@@ -0,0 +1,93 @@
+/**
+ * @fileoverview Ensures consistent parameter names in blaze event maps
+ * @author Philipp Sporrer, Dominik Ferber
+ * @copyright 2015 Philipp Sporrer. All rights reserved.
+ * See LICENSE file in root directory for full license.
+ */
+
+import {isFunction, isTemplateProp} from '../util/ast'
+import {getExecutors} from '../util'
+import {NON_METEOR} from '../util/environment'
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+module.exports = getMeta => context => {
+
+  const {env} = getMeta(context)
+
+  // ---------------------------------------------------------------------------
+  // Helpers
+  // ---------------------------------------------------------------------------
+
+  function ensureParamName (param, expectedParamName) {
+    if (param && param.name !== expectedParamName) {
+      context.report(
+        param,
+        `Invalid parameter name, use "${expectedParamName}" instead`
+      )
+    }
+  }
+
+  function validateEventDef (eventDefNode) {
+
+    const eventHandler = eventDefNode.value
+    if (isFunction(eventHandler.type)) {
+
+      ensureParamName(
+        eventHandler.params[0],
+        context.options[0] ? context.options[0].eventParamName : 'event'
+      )
+
+      ensureParamName(
+        eventHandler.params[1],
+        context.options[0] ? context.options[0].templateInstanceParamName : 'templateInstance'
+      )
+    }
+
+  }
+
+  // ---------------------------------------------------------------------------
+  // Public
+  // ---------------------------------------------------------------------------
+
+  if (env === NON_METEOR) {
+    return {}
+  }
+
+  return {
+
+    CallExpression: function (node) {
+
+      if (node.arguments.length === 0 || !isTemplateProp(node.callee, 'events')) {
+        return
+      }
+      const executors = getExecutors(env, context.getAncestors())
+      if (executors.has('browser') || executors.has('cordova')) {
+        const eventMap = node.arguments[0]
+
+        if (eventMap.type === 'ObjectExpression') {
+          eventMap.properties.forEach((eventDef) => validateEventDef(eventDef))
+        }
+      }
+    }
+
+  }
+
+}
+
+module.exports.schema = [
+  {
+    type: 'object',
+    properties: {
+      eventParamName: {
+        type: 'string'
+      },
+      templateInstanceParamName: {
+        type: 'string'
+      }
+    },
+    additionalProperties: false
+  }
+]

lib/util/ast/index.js

@@ -1,5 +1,6 @@
 export {default as isMeteorCall} from './isMeteorCall'
 export {default as isMeteorProp} from './isMeteorProp'
+export {default as isTemplateProp} from './isTemplateProp'
 export {default as isFunction} from './isFunction'
 export {default as getPropertyName} from './getPropertyName'
 export {default as areRefsTrackable} from './areRefsTrackable'

lib/util/ast/isTemplateProp.js

@@ -0,0 +1,10 @@
+import getPropertyName from './getPropertyName'
+
+export default function (node, propName) {
+  return (
+    node.type === 'MemberExpression' &&
+    node.object.type === 'MemberExpression' &&
+    node.object.object.type === 'Identifier' && node.object.object.name === 'Template' &&
+    getPropertyName(node.property) === propName
+  )
+}