cleanup #58

Author: sindresorhus

docs/rules/no-array-instanceof.md

@@ -1,6 +1,7 @@
-# Require  `Array.isArray()` check instead of `instanceof Array`
+# Require `Array.isArray()` instead of `instanceof Array`
+
+The `instanceof Array` check doesn't work across realms/contexts, for example, frames/windows in browsers or the `vm` module in Node.js.
 
-While the `instanceof Array` works, it is unreliable across environments Eg: multi-frame DOM environments (iframes). Hence, `Array.isArray()` is recommended.
 
 ## Fail
 
@@ -9,6 +10,7 @@ array instanceof Array;
 [1,2,3] instanceof Array;
 ```
 
+
 ## Pass
 
 ```js

index.js

@@ -19,8 +19,8 @@ module.exports = {
 				'unicorn/no-abusive-eslint-disable': 'error',
 				'unicorn/no-process-exit': 'error',
 				'unicorn/throw-new-error': 'error',
-				'unicorn/no-array-instanceof': 'error',
-				'unicorn/number-literal-case': 'error'
+				'unicorn/number-literal-case': 'error',
+				'unicorn/no-array-instanceof': 'error'
 			}
 		}
 	}

readme.md

@@ -56,7 +56,7 @@ Configure it in `package.json`.
 - [no-process-exit](docs/rules/no-process-exit.md) - Disallow `process.exit()`.
 - [throw-new-error](docs/rules/throw-new-error.md) - Require `new` when throwing an error. *(fixable)*
 - [number-literal-case](docs/rules/number-literal-case.md) - Enforce lowercase identifier and uppercase value for number literals. *(fixable)*
-- [no-array-instanceof](docs/rules/no-array-instanceof.md) - Disallow `instanceof Array`, instead use `Array.isArray()`. *(fixable)*
+- [no-array-instanceof](docs/rules/no-array-instanceof.md) - Require `Array.isArray()` instead of `instanceof Array`. *(fixable)*
 
 
 ## Recommended config

rules/no-array-instanceof.js

@@ -3,11 +3,12 @@
 const create = context => ({
 	BinaryExpression: node => {
 		if (node.operator === 'instanceof' && node.right.type === 'Identifier' && node.right.name === 'Array') {
-			// Get the source code and extract the left part.
+			// get the source code and extract the left part
 			const arraySourceCode = context.getSourceCode().text.slice(node.left.range[0], node.left.range[1]);
+
 			context.report({
 				node,
-				message: 'Use `Array.isArray()` instead of `instanceof Array`',
+				message: 'Use `Array.isArray()` instead of `instanceof Array`.',
 				fix: fixer => fixer.replaceText(node, `Array.isArray(${arraySourceCode})`)
 			});
 		}

test/no-array-instanceof.js

@@ -10,7 +10,7 @@ const ruleTester = avaRuleTester(test, {
 
 const errors = [{
 	ruleId: 'no-array-instanceof',
-	message: 'Use `Array.isArray()` instead of `instanceof Array`'
+	message: 'Use `Array.isArray()` instead of `instanceof Array`.'
 }];
 
 ruleTester.run('avoid-array-instanceof', rule, {