Add prefer-number-properties rule (#622)

Co-authored-by: Sindre Sorhus <[email protected]>

Author: fisker

docs/rules/prefer-number-properties.md

@@ -0,0 +1,60 @@
+# Prefer `Number` static properties over global ones.
+
+Enforces the use of:
+
+- [`Number.parseInt()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseInt) over [`parseInt()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt) *(fixable)*
+- [`Number.parseFloat()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseFloat) over [`parseFloat()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseFloat) *(fixable)*
+- [`Number.isNaN()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN) over [`isNaN()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN) *(they have slightly [different behavior](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN#Description))*
+- [`Number.isFinite()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isFinite) over [`isFinite()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isFinite) *(they have slightly [different behavior](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isFinite#Description))*
+- [`Number.NaN`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/NaN) over [`NaN`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/NaN) *(fixable)*
+
+This rule is partly fixable.
+
+## Fail
+
+```js
+const foo = parseInt('10', 2);
+```
+
+```js
+const foo = parseFloat('10.5');
+```
+
+```js
+const foo = isNaN(10);
+```
+
+```js
+const foo = isFinite(10);
+```
+
+```js
+if (Object.is(foo, NaN)) {}
+```
+
+```js
+const {parseInt} = Number;
+const foo = parseInt('10', 2);
+```
+
+## Pass
+
+```js
+const foo = Number.parseInt('10', 2);
+```
+
+```js
+const foo = Number.parseFloat('10.5');
+```
+
+```js
+const foo = Number.isNaN(10);
+```
+
+```js
+const foo = Number.isFinite(10);
+```
+
+```js
+if (Object.is(foo, Number.NaN)) {}
+```

index.js

@@ -53,6 +53,7 @@ module.exports = {
 				'unicorn/prefer-negative-index': 'error',
 				'unicorn/prefer-node-append': 'error',
 				'unicorn/prefer-node-remove': 'error',
+				'unicorn/prefer-number-properties': 'error',
 				'unicorn/prefer-query-selector': 'error',
 				'unicorn/prefer-reflect-apply': 'error',
 				// TODO: Enable this by default when it's shipping in a Node.js LTS version.

readme.md

@@ -69,6 +69,7 @@ Configure it in `package.json`.
 			"unicorn/prefer-negative-index": "error",
 			"unicorn/prefer-node-append": "error",
 			"unicorn/prefer-node-remove": "error",
+			"unicorn/prefer-number-properties": "error",
 			"unicorn/prefer-query-selector": "error",
 			"unicorn/prefer-reflect-apply": "error",
 			"unicorn/prefer-replace-all": "off",
@@ -124,6 +125,7 @@ Configure it in `package.json`.
 - [prefer-negative-index](docs/rules/prefer-negative-index.md) - Prefer negative index over `.length - index` for `{String,Array,TypedArray}#slice()` and `Array#splice()`. *(fixable)*
 - [prefer-node-append](docs/rules/prefer-node-append.md) - Prefer `Node#append()` over `Node#appendChild()`. *(fixable)*
 - [prefer-node-remove](docs/rules/prefer-node-remove.md) - Prefer `childNode.remove()` over `parentNode.removeChild(childNode)`. *(fixable)*
+- [prefer-number-properties](docs/rules/prefer-number-properties.md) - Prefer `Number` static properties over global ones. *(fixable)*
 - [prefer-query-selector](docs/rules/prefer-query-selector.md) - Prefer `.querySelector()` over `.getElementById()`, `.querySelectorAll()` over `.getElementsByClassName()` and `.getElementsByTagName()`. *(partly fixable)*
 - [prefer-reflect-apply](docs/rules/prefer-reflect-apply.md) - Prefer `Reflect.apply()` over `Function#apply()`. *(fixable)*
 - [prefer-replace-all](docs/rules/prefer-replace-all.md) - Prefer `String#replaceAll()` over regex searches with the global flag. *(fixable)*

rules/prefer-number-properties.js

@@ -0,0 +1,115 @@
+'use strict';
+const getDocumentationUrl = require('./utils/get-documentation-url');
+const isShadowed = require('./utils/is-shadowed');
+const renameIdentifier = require('./utils/rename-identifier');
+
+const methodMessageId = 'method';
+const propertyMessageId = 'property';
+
+const methods = {
+	// Safe
+	parseInt: true,
+	parseFloat: true,
+	// Unsafe
+	isNaN: false,
+	isFinite: false
+};
+
+const methodsSelector = [
+	'CallExpression',
+	'>',
+	'Identifier',
+	`:matches(${Object.keys(methods).map(name => `[name="${name}"]`).join(', ')})`
+].join('');
+
+const propertiesSelector = [
+	`:not(${
+		[
+			'MemberExpression[computed=false]',
+			'FunctionDeclaration',
+			'ClassDeclaration',
+			'MethodDefinition'
+		].join(', ')
+	})`,
+	'>',
+	'Identifier',
+	'[name="NaN"]'
+].join('');
+
+const create = context => {
+	const sourceCode = context.getSourceCode();
+
+	return {
+		[methodsSelector]: node => {
+			if (isShadowed(context.getScope(), node)) {
+				return;
+			}
+
+			const {name} = node;
+			const isSafe = methods[name];
+
+			const problem = {
+				node,
+				messageId: methodMessageId,
+				data: {
+					name
+				}
+			};
+
+			const fix = fixer => renameIdentifier(node, `Number.${name}`, fixer, sourceCode);
+
+			if (isSafe) {
+				problem.fix = fix;
+			} else {
+				problem.suggest = [{messageId: methodMessageId, fix}];
+			}
+
+			context.report(problem);
+		},
+		[propertiesSelector]: node => {
+			if (isShadowed(context.getScope(), node)) {
+				return;
+			}
+
+			const {parent} = node;
+
+			if (
+				parent &&
+				(
+					(parent.type === 'VariableDeclarator' && parent.id === node) ||
+					(parent.type === 'Property' && !parent.shorthand && parent.key === node) ||
+					(parent.type === 'TSDeclareFunction' && parent.id === node) ||
+					parent.type === 'TSEnumMember' ||
+					parent.type === 'TSPropertySignature'
+				)
+			) {
+				return;
+			}
+
+			const {name} = node;
+			context.report({
+				node,
+				messageId: propertyMessageId,
+				data: {
+					name
+				},
+				fix: fixer => renameIdentifier(node, `Number.${name}`, fixer, sourceCode)
+			});
+		}
+	};
+};
+
+module.exports = {
+	create,
+	meta: {
+		type: 'suggestion',
+		docs: {
+			url: getDocumentationUrl(__filename)
+		},
+		fixable: 'code',
+		messages: {
+			[methodMessageId]: 'Prefer `Number.{{name}}()` over `{{name}}()`.',
+			[propertyMessageId]: 'Prefer `Number.{{name}}` over `{{name}}`.'
+		}
+	}
+};