add cache option rule (#29)

* add cache option rule

* Update warning for the cache: false option

* Update cache-false.spec.js

Author: kazupon

rules/vue/cache-false.js

@@ -0,0 +1,15 @@
+'use strict'
+
+var chalk = require('chalk')
+
+module.exports = {
+  pattern: /\bcache\s*?:\s*?false\b/,
+  warning: function (match) {
+    return {
+      reason: 'The cache option on computed properties has been deprecated, as it\'s better to simply use a method instead',
+      fix: 'Refactor the computed property into a method',
+      docsHash: 'cache-false',
+      type: 'js'
+    }
+  }
+}

rules/vue/cache-false.spec.js

@@ -0,0 +1,39 @@
+'use strict'
+
+const check = createRuleChecker('vue/cache-false')
+
+describe('Rule: cache-false', () => {
+  it('does not match an empty line', () => {
+    const warning = check('')
+    expect(warning).toBe(null)
+  })
+
+  it('does not match "cache"', () => {
+    const warning = check('cache')
+    expect(warning).toBe(null)
+  })
+
+  it('matches "cache: false,"', () => {
+    const warning = check(`
+      cache: false,
+    `)
+    expect(warning).toBeTruthy()
+    expect(warning.fix).toBe('Refactor the computed property into a method')
+  })
+
+  it('matches "cache:false,"', () => {
+    const warning = check(`
+      cache:false,
+    `)
+    expect(warning).toBeTruthy()
+    expect(warning.fix).toBe('Refactor the computed property into a method')
+  })
+
+  it('matches "cache: false,"', () => {
+    const warning = check(`
+      cache : false,
+    `)
+    expect(warning).toBeTruthy()
+    expect(warning.fix).toBe('Refactor the computed property into a method')
+  })
+})