Merge pull request #11 from chadhietala/no-attrs-snapshot

Add no-attrs-snapshot rule

Author: chadhietala

RULES.md

@@ -2,10 +2,8 @@
 
 These are rules we would like to enforce:
 
-no-attrs-snapshots
-no-timers
-no-mixins
-no-sub-classes
-detect-stateless-service
-eager-injections
-no-send-action
+- no-mixins
+- no-sub-classes
+- detect-stateless-service
+- eager-injections
+- no-send-action

lib/rules/no-attrs-snapshot.js

@@ -0,0 +1,22 @@
+function hasAttrsSnapShot(node) {
+  let methodName = node.parent.key.name;
+  let hasParams = node.params.length > 0;
+  return (methodName === 'didReceiveAttrs' || methodName === 'didUpdateAttrs') && hasParams;
+}
+
+const MESSAGE = 'Do not use the attrs snapshot that is passed in `didReceiveAttrs` and `didUpdateAttrs`. Please see the following guide for more infromation: https://github.com/chadhietala/ember-best-practices/blob/master/guides/rules/no-attrs-snapshot.md';
+
+module.exports = {
+  meta: {
+    message: MESSAGE
+  },
+  create(context) {
+    return {
+      FunctionExpression(node) {
+        if (hasAttrsSnapShot(node)) {
+          context.report(node, MESSAGE);
+        }
+      }
+    };
+  }
+};

tests/lib/rules/no-attrs-snapshot.js

@@ -0,0 +1,103 @@
+const rule = require('../../../lib/rules/no-attrs-snapshot');
+const MESSAGE = rule.meta.message;
+const RuleTester = require('eslint').RuleTester;
+const ruleTester = new RuleTester();
+
+ruleTester.run('no-attrs-snapshot', rule, {
+  valid: [
+    {
+      code: `
+        export default Ember.Component({
+          init() {
+            this._super(...arguments);
+            this._valueCache = this.value;
+            this.updated = false;
+          },
+          didReceiveAttrs() {
+            if (this._valueCache !== this.value) {
+              this._valueCache = this.value;
+              this.set('updated', true);
+            } else {
+              this.set('updated', false);
+            }
+          }
+        });`,
+      parserOptions: {
+        ecmaVersion: 6,
+        sourceType: 'module'
+      }
+    },
+    {
+      code: `
+        export default Ember.Component({
+          init() {
+            this._super(...arguments);
+            this._valueCache = this.value;
+            this.updated = false;
+          },
+          didUpdateAttrs() {
+            if (this._valueCache !== this.value) {
+              this._valueCache = this.value;
+              this.set('updated', true);
+            } else {
+              this.set('updated', false);
+            }
+          }
+        });`,
+      parserOptions: {
+        ecmaVersion: 6,
+        sourceType: 'module'
+      }
+    }
+  ],
+  invalid: [
+    {
+      code: `
+        export default Ember.Component({
+          init() {
+            this._super(...arguments);
+            this.updated = false;
+          },
+          didReceiveAttrs(attrs) {
+            let { newAttrs, oldAttrs } = attrs;
+            if ((newAttrs && oldAttrs) && newAttrs.value !== oldAttrs.value) {
+              this.set('updated', true);
+            } else {
+              this.set('updated', false);
+            }
+          }
+        });`,
+      parserOptions: {
+        ecmaVersion: 6,
+        sourceType: 'module'
+      },
+      errors: [{
+        message: MESSAGE
+      }]
+    },
+    {
+      code: `
+        export default Ember.Component({
+          init() {
+            this._super(...arguments);
+            this.updated = false;
+          },
+          didUpdateAttrs(attrs) {
+            let { newAttrs, oldAttrs } = attrs;
+            if ((newAttrs && oldAttrs) && newAttrs.value !== oldAttrs.value) {
+              this.set('updated', true);
+            } else {
+              this.set('updated', false);
+            }
+          }
+        });`,
+      parserOptions: {
+        ecmaVersion: 6,
+        sourceType: 'module'
+      },
+      errors: [{
+        message: MESSAGE
+      }]
+    }
+  ]
+});