feat: add strict option to disallow then or catch following await or yield; fixes #294

Author: brettz9

__tests__/prefer-await-to-then.js

@@ -15,6 +15,7 @@ ruleTester.run('prefer-await-to-then', rule, {
     'async function hi() { await thing() }',
     'async function hi() { await thing().then() }',
     'async function hi() { await thing().catch() }',
+    'function * hi() { yield thing().then() }',
     'a = async () => (await something())',
     `a = async () => {
       try { await something() } catch (error) { somethingElse() }
@@ -54,5 +55,32 @@ ruleTester.run('prefer-await-to-then', rule, {
       code: 'function foo() { hey.finally(x => {}) }',
       errors: [{ message }],
     },
+    {
+      code: 'async function hi() { await thing().then() }',
+      errors: [{ message }],
+      options: [
+        {
+          strict: true,
+        },
+      ],
+    },
+    {
+      code: 'async function hi() { await thing().catch() }',
+      errors: [{ message }],
+      options: [
+        {
+          strict: true,
+        },
+      ],
+    },
+    {
+      code: 'function * hi() { yield thing().then() }',
+      errors: [{ message }],
+      options: [
+        {
+          strict: true,
+        },
+      ],
+    },
   ],
 })

docs/rules/prefer-await-to-then.md

@@ -44,3 +44,18 @@ function exampleFour() {
   return myPromise.finally(cleanup)
 }
 ```
+
+## Options
+
+### `strict`
+
+Normally, this rule allows `then` or `catch` following an `await` (or `yield`)
+expression. Setting this option to `true` will err on such cases:
+
+This will fail with the `strict` option:
+
+```js
+async function hi() {
+  await thing().then()
+}
+```

rules/prefer-await-to-then.js

@@ -16,7 +16,16 @@ module.exports = {
         'Prefer `await` to `then()`/`catch()`/`finally()` for reading Promise values.',
       url: getDocsUrl('prefer-await-to-then'),
     },
-    schema: [],
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          strict: {
+            type: 'boolean',
+          },
+        },
+      },
+    ],
     messages: {
       preferAwaitToCallback: 'Prefer await to then()/catch()/finally().',
     },
@@ -40,9 +49,11 @@ module.exports = {
       return getScope(context, node).block.type === 'Program'
     }
 
+    const { strict } = context.options[0] || {}
+
     return {
       'CallExpression > MemberExpression.callee'(node) {
-        if (isTopLevelScoped(node) || isInsideYieldOrAwait(node)) {
+        if (isTopLevelScoped(node) || (!strict && isInsideYieldOrAwait(node))) {
           return
         }