whitelist cy commands that synchronously return values

Author: chrisbreiding

lib/rules/no-assigning-return-values.js

@@ -5,6 +5,17 @@
 
 'use strict'
 
+// safely get nested object property
+function get (obj, propertyString = '') {
+  const properties = propertyString.split('.')
+  for (let i = 0; i < properties.length; i++) {
+    const value = (obj || {})[properties[i]]
+    if (value == null) return value
+    obj = value
+  }
+  return obj
+}
+
 module.exports = {
   meta: {
     docs: {
@@ -29,21 +40,27 @@ module.exports = {
   },
 }
 
-function isCypressCommandDeclaration (declarator) {
-  if (!declarator) { return }
-  if (!declarator.init) { return }
-  if (!declarator.init.callee) { return }
+const whitelistedCommands = {
+  now: true,
+  spy: true,
+  state: true,
+  stub: true,
+}
 
-  let object = declarator.init.callee.object
+function isCypressCommandDeclaration (declarator) {
+  let object = get(declarator, 'init.callee.object')
 
-  if (!object) { return }
+  if (!object) return
 
   while (object.callee) {
     object = object.callee.object
-    if (!object) {
-      return
-    }
+
+    if (!object) return
   }
 
+  const commandName = get(object, 'parent.property.name')
+
+  if (commandName && whitelistedCommands[commandName]) return
+
   return object.name === 'cy'
 }

tests/lib/rules/no-assigning-return-values.js

@@ -15,6 +15,10 @@ ruleTester.run('no-assigning-return-values', rule, {
     { code: 'const foo = true;', parserOptions },
     { code: 'const foo = bar();', parserOptions },
     { code: 'const foo = bar().baz();', parserOptions },
+    { code: 'const spy = cy.spy();', parserOptions },
+    { code: 'const stub = cy.stub();', parserOptions },
+    { code: 'const result = cy.now();', parserOptions },
+    { code: 'const state = cy.state();', parserOptions },
     { code: 'cy.get("foo");', parserOptions },
     { code: 'cy.contains("foo").click();', parserOptions },
   ],