fix(prefer-in-document): check that a node has arguments before trying to access properties on them (#165)

* fix(prefer-in-document): handle `toHaveLength` without arguments

* fix(prefer-in-document): add array length guards

Author: G-Rath

src/__tests__/lib/rules/prefer-in-document.js

@@ -36,6 +36,9 @@ const valid = [
       foo = somethingElse;
       expect(foo).toHaveLength(1);`,
   ]),
+  `expect().not.toBeNull()`,
+  `expect(myFunction()).toBe();`,
+  `expect(myFunction()).toHaveLength();`,
   `let foo;
   foo = "bar";
   expect(foo).toHaveLength(1);`,

src/rules/prefer-in-document.js

@@ -32,8 +32,10 @@ function isAntonymMatcher(matcherNode, matcherArguments) {
 }
 
 function usesToBeOrToEqualWithNull(matcherNode, matcherArguments) {
-  return (matcherNode.name === "toBe" || matcherNode.name === "toEqual") &&
-    matcherArguments[0].value === null;
+  return (
+    (matcherNode.name === "toBe" || matcherNode.name === "toEqual") &&
+    matcherArguments[0].value === null
+  );
 }
 
 function usesToHaveLengthZero(matcherNode, matcherArguments) {
@@ -71,7 +73,7 @@ export const create = (context) => {
     if (!queryNode || (!queryNode.name && !queryNode.property)) return;
 
     // toHaveLength() is only invalid with 0 or 1
-    if (matcherNode.name === "toHaveLength") {
+    if (matcherNode.name === "toHaveLength" && matcherArguments.length) {
       const lengthValue = getLengthValue(matcherArguments);
       // isNotToHaveLengthZero represents .not.toHaveLength(0) which is a valid use of toHaveLength
       const isNotToHaveLengthZero =
@@ -89,7 +91,10 @@ export const create = (context) => {
 
     // toBe() or toEqual() are only invalid with null
     if (matcherNode.name === "toBe" || matcherNode.name === "toEqual") {
-      if (!usesToBeOrToEqualWithNull(matcherNode, matcherArguments)) {
+      if (
+        !matcherArguments.length ||
+        !usesToBeOrToEqualWithNull(matcherNode, matcherArguments)
+      ) {
         return;
       }
     }
@@ -146,6 +151,10 @@ export const create = (context) => {
     [`CallExpression[callee.object.object.callee.name='expect'][callee.object.property.name='not'][callee.property.name=${alternativeMatchers}], CallExpression[callee.object.callee.name='expect'][callee.object.property.name='not'][callee.object.arguments.0.argument.callee.name=${alternativeMatchers}]`](
       node
     ) {
+      if (!node.callee.object.object.arguments.length) {
+        return;
+      }
+
       const arg = node.callee.object.object.arguments[0];
       const queryNode =
         arg.type === "AwaitExpression" ? arg.argument.callee : arg.callee;