Import-blacklist: simplify check for if module has blacklisted imports

src/rules/importBlacklistRule.ts

@@ -18,7 +18,6 @@
 import { findImports, ImportKind, isExportDeclaration, isImportDeclaration, isNamedImports } from "tsutils";
 import * as ts from "typescript";
 import * as Lint from "../index";
-import { hasOwnProperty } from "../utils";
 
 export class Rule extends Lint.Rules.AbstractRule {
     /* tslint:disable:object-literal-sort-keys */
@@ -114,7 +113,7 @@ function walk(ctx: Lint.WalkContext<string[]>) {
             }
             return acc;
         },
-        {},
+        Object.create(null),
     );
 
     for (const name of findImports(ctx.sourceFile, ImportKind.All)) {
@@ -123,7 +122,7 @@ function walk(ctx: Lint.WalkContext<string[]>) {
         const bansForModule = bannedImports[importedModule];
 
         // Check if at least some imports from this module are banned.
-        if (hasOwnProperty(bannedImports, importedModule)) {
+        if (bansForModule) {
             // If importing this module is totally banned, we can error now,
             // without determining whether the user is importing the whole
             // module or named exports.