Safely check all array accesses (#749)

Author: danez

.eslintrc.cjs

@@ -56,6 +56,7 @@ module.exports = {
         '@typescript-eslint/ban-ts-comment': 'off',
         '@typescript-eslint/consistent-type-imports': 'error',
         '@typescript-eslint/no-duplicate-imports': 'error',
+        '@typescript-eslint/no-non-null-assertion': 'off',
         '@typescript-eslint/sort-type-union-intersection-members': 'error',
       },
     },

packages/react-docgen-cli/src/commands/parse/options/loadReactDocgenPlugin.ts

@@ -7,7 +7,7 @@ export default async function loadReactDocgenPlugin<T>(
   builtins?: Record<string, T>,
 ): Promise<T> {
   if (builtins?.[input]) {
-    return builtins[input];
+    return builtins[input]!;
   }
 
   const path = resolve(process.cwd(), input);

packages/react-docgen-cli/src/commands/parse/options/loadResolvers.ts

@@ -54,5 +54,5 @@ export default async function loadResolvers(
     });
   }
 
-  return loadResolver(input[0]);
+  return loadResolver(input[0]!);
 }

packages/react-docgen/src/handlers/componentMethodsHandler.ts

@@ -103,7 +103,7 @@ const explodedImperativeHandleVisitors =
         // useImperativeHandle(ref, () => ({ name: () => {}, ...}))
         const arg = path.get('arguments')[1];
 
-        if (arg && !arg.isFunction()) {
+        if (!arg || !arg.isFunction()) {
           return path.skip();
         }
 

packages/react-docgen/src/resolver/FindAllDefinitionsResolver.ts

@@ -53,20 +53,24 @@ const explodedVisitors = visitors.explode<TraverseState>({
   ClassDeclaration: { enter: classVisitor },
   CallExpression: {
     enter: function (path, state): void {
+      const argument = path.get('arguments')[0];
+
+      if (!argument) {
+        return;
+      }
+
       if (isReactForwardRefCall(path)) {
         // If the the inner function was previously identified as a component
         // replace it with the parent node
-        const inner = resolveToValue(
-          path.get('arguments')[0],
-        ) as ComponentNodePath;
+        const inner = resolveToValue(argument) as ComponentNodePath;
 
         state.foundDefinitions.delete(inner);
         state.foundDefinitions.add(path);
 
         // Do not traverse into arguments
         return path.skip();
       } else if (isReactCreateClassCall(path)) {
-        const resolvedPath = resolveToValue(path.get('arguments')[0]);
+        const resolvedPath = resolveToValue(argument);
 
         if (resolvedPath.isObjectExpression()) {
           state.foundDefinitions.add(resolvedPath);

packages/react-docgen/src/utils/docblock.ts

@@ -35,7 +35,7 @@ export function getDocblock(path: NodePath, trailing = false): string | null {
   }
 
   if (comments.length > 0) {
-    return parseDocblock(comments[comments.length - 1].value);
+    return parseDocblock(comments[comments.length - 1]!.value);
   }
 
   return null;
@@ -50,7 +50,7 @@ export function getDoclets(str: string): Record<string, string> {
   let match: RegExpExecArray | null;
 
   while ((match = DOCLET_PATTERN.exec(str))) {
-    doclets[match[1]] = match[2] || true;
+    doclets[match[1]!] = match[2] || true;
   }
 
   return doclets;

packages/react-docgen/src/utils/getFlowType.ts

@@ -159,7 +159,7 @@ function handleGenericTypeAnnotation(
   if (
     typeParams &&
     typeParams[type.name] &&
-    typeParams[type.name].isGenericTypeAnnotation()
+    typeParams[type.name]!.isGenericTypeAnnotation()
   ) {
     return type;
   }

packages/react-docgen/src/utils/getMemberExpressionValuePath.ts

@@ -17,7 +17,8 @@ function resolveName(path: NodePath): string | undefined {
           ' declarations.',
       );
     }
-    const id = declarations[0].get('id');
+    // VariableDeclarator always has at least one declaration, hence the non-null-assertion
+    const id = declarations[0]!.get('id');
 
     if (id.isIdentifier()) {
       return id.node.name;

packages/react-docgen/src/utils/getTSType.ts

@@ -207,15 +207,19 @@ function handleTSTypeLiteral(
     } else if (param.isTSCallSignatureDeclaration()) {
       type.signature.constructor = handleTSFunctionType(param, typeParams);
     } else if (param.isTSIndexSignature() && typeAnnotation.hasNode()) {
-      const idTypeAnnotation = param
-        .get('parameters')[0]
-        .get('typeAnnotation') as NodePath<TSTypeAnnotation | null | undefined>;
-
-      if (idTypeAnnotation.hasNode()) {
-        type.signature.properties.push({
-          key: getTSTypeWithResolvedTypes(idTypeAnnotation, typeParams),
-          value: getTSTypeWithRequirements(typeAnnotation, typeParams),
-        });
+      const parameters = param.get('parameters');
+
+      if (parameters[0]) {
+        const idTypeAnnotation = parameters[0].get(
+          'typeAnnotation',
+        ) as NodePath<TSTypeAnnotation | null | undefined>;
+
+        if (idTypeAnnotation.hasNode()) {
+          type.signature.properties.push({
+            key: getTSTypeWithResolvedTypes(idTypeAnnotation, typeParams),
+            value: getTSTypeWithRequirements(typeAnnotation, typeParams),
+          });
+        }
       }
     }
   });

packages/react-docgen/src/utils/getTypeFromReactComponent.ts

@@ -52,7 +52,9 @@ export default (path: NodePath): NodePath | null => {
     if (superTypes.hasNode()) {
       const params = superTypes.get('params');
 
-      typePath = params[params.length === 3 ? 1 : 0];
+      if (params.length >= 1) {
+        typePath = params[params.length === 3 ? 1 : 0]!;
+      }
     } else {
       const propsMemberPath = getMemberValuePath(path, 'props');