prefer-number-properties: Add Infinity support (#874)

docs/rules/prefer-number-properties.md

@@ -7,6 +7,8 @@ Enforces the use of:
 - [`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)*
+- [`Number.POSITIVE_INFINITY`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/POSITIVE_INFINITY) over [`Infinity`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Infinity) *(fixable)*
+- [`Number.NEGATIVE_INFINITY`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/NEGATIVE_INFINITY) over [`-Infinity`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Infinity) *(fixable)*
 
 This rule is partly fixable.
 
@@ -32,6 +34,14 @@ const foo = isFinite(10);
 if (Object.is(foo, NaN)) {}
 ```
 
+```js
+const isPositiveZero = value => value === 0 && 1 / value === Infinity;
+```
+
+```js
+const isNegativeZero = value => value === 0 && 1 / value === -Infinity;
+```
+
 ```js
 const {parseInt} = Number;
 const foo = parseInt('10', 2);
@@ -58,3 +68,46 @@ const foo = Number.isFinite(10);
 ```js
 if (Object.is(foo, Number.NaN)) {}
 ```
+
+```js
+const isPositiveZero = value => value === 0 && 1 / value === Number.POSITIVE_INFINITY;
+```
+
+```js
+const isNegativeZero = value => value === 0 && 1 / value === Number.NEGATIVE_INFINITY;
+```
+
+# Options
+
+Type: `object`
+
+### checkInfinity
+
+Type: `boolean`\
+Default: `true`
+
+Pass `checkInfinity: false` to disable check on `Infinity`.
+
+#### Fail
+
+```js
+// eslint unicorn/prefer-number-properties: ["error", {checkInfinity: true}]
+const foo = Infinity;
+```
+
+```js
+// eslint unicorn/prefer-number-properties: ["error", {checkInfinity: true}]
+const foo = -Infinity;
+```
+
+#### Pass
+
+```js
+// eslint unicorn/prefer-number-properties: ["error", {checkInfinity: false}]
+const foo = Infinity;
+```
+
+```js
+// eslint unicorn/prefer-number-properties: ["error", {checkInfinity: false}]
+const foo = -Infinity;
+```

rules/prefer-number-properties.js

@@ -9,7 +9,7 @@ const PROPERTY_ERROR_MESSAGE_ID = 'property-error';
 const messages = {
 	[METHOD_ERROR_MESSAGE_ID]: 'Prefer `Number.{{name}}()` over `{{name}}()`.',
 	[METHOD_SUGGESTION_MESSAGE_ID]: 'Replace `{{name}}()` with `Number.{{name}}()`.',
-	[PROPERTY_ERROR_MESSAGE_ID]: 'Prefer `Number.{{name}}` over `{{name}}`.'
+	[PROPERTY_ERROR_MESSAGE_ID]: 'Prefer `Number.{{property}}` over `{{identifier}}`.'
 };
 
 const methods = {
@@ -30,7 +30,7 @@ const methodsSelector = [
 
 const propertiesSelector = [
 	'Identifier',
-	'[name="NaN"]',
+	':matches([name="NaN"],[name="Infinity"])',
 	`:not(${
 		[
 			'MemberExpression[computed=false] > Identifier.property',
@@ -46,10 +46,19 @@ const propertiesSelector = [
 	})`
 ].join('');
 
+const isNegative = node => {
+	const {parent} = node;
+	return parent && parent.type === 'UnaryExpression' && parent.operator === '-' && parent.argument === node;
+};
+
 const create = context => {
 	const sourceCode = context.getSourceCode();
+	const options = {
+		checkInfinity: true,
+		...context.options[0]
+	};
 
-	// Cache `NaN` in `foo = {NaN}`
+	// Cache `NaN` and `Infinity` in `foo = {NaN, Infinity}`
 	const reported = new WeakSet();
 
 	return {
@@ -93,20 +102,51 @@ const create = context => {
 			}
 
 			const {name} = node;
-			context.report({
+			if (name === 'Infinity' && !options.checkInfinity) {
+				return;
+			}
+
+			let property = name;
+			if (name === 'Infinity') {
+				property = isNegative(node) ? 'NEGATIVE_INFINITY' : 'POSITIVE_INFINITY';
+			}
+
+			const problem = {
 				node,
 				messageId: PROPERTY_ERROR_MESSAGE_ID,
 				data: {
-					name
-				},
-				fix: fixer => renameIdentifier(node, `Number.${name}`, fixer, sourceCode)
-			});
+					identifier: name,
+					property
+				}
+			};
+
+			if (property === 'NEGATIVE_INFINITY') {
+				problem.node = node.parent;
+				problem.data.identifier = '-Infinity';
+				problem.fix = fixer => fixer.replaceText(node.parent, 'Number.NEGATIVE_INFINITY');
+			} else {
+				problem.fix = fixer => renameIdentifier(node, `Number.${property}`, fixer, sourceCode);
+			}
 
+			context.report(problem);
 			reported.add(node);
 		}
 	};
 };
 
+const schema = [
+	{
+		type: 'object',
+		properties: {
+			checkInfinity: {
+				type: 'boolean',
+				default: true
+			}
+		},
+		additionalProperties: false
+	}
+];
+
 module.exports = {
 	create,
 	meta: {
@@ -115,6 +155,7 @@ module.exports = {
 			url: getDocumentationUrl(__filename)
 		},
 		fixable: 'code',
+		schema,
 		messages
 	}
 };

rules/utils/cartesian-product-samples.js

@@ -9,7 +9,7 @@ const getTotal = combinations => {
 	return total;
 };
 
-module.exports = (combinations, length = Infinity) => {
+module.exports = (combinations, length = Number.POSITIVE_INFINITY) => {
 	const total = getTotal(combinations);
 
 	const samples = Array.from({length: Math.min(total, length)}, (_, sampleIndex) => {

rules/utils/method-selector.js

@@ -11,7 +11,7 @@ module.exports = options => {
 		property = ''
 	} = {
 		min: 0,
-		max: Infinity,
+		max: Number.POSITIVE_INFINITY,
 		...options
 	};
 

test/prefer-number-properties.js

@@ -153,12 +153,13 @@ test({
 	]
 });
 
-// NaN
+// `NaN` and `Infinity`
 const errorNaN = [
 	{
 		messageId: PROPERTY_ERROR_MESSAGE_ID,
 		data: {
-			name: 'NaN'
+			identifier: 'NaN',
+			property: 'NaN'
 		}
 	}
 ];
@@ -167,6 +168,8 @@ test({
 		'const foo = Number.NaN;',
 		'const foo = window.Number.NaN;',
 		'const foo = bar.NaN;',
+		'const foo = nan;',
+		'const foo = "NaN";',
 		// Shadowed
 		outdent`
 			function foo () {
@@ -177,7 +180,36 @@ test({
 		'const {NaN} = {};',
 		'function NaN() {}',
 		'class NaN {}',
-		'class Foo { NaN(){}}'
+		'class Foo { NaN(){}}',
+
+		'const foo = Number.POSITIVE_INFINITY;',
+		'const foo = window.Number.POSITIVE_INFINITY;',
+		'const foo = bar.POSITIVE_INFINITY;',
+		'const foo = Number.Infinity;',
+		'const foo = window.Number.Infinity;',
+		'const foo = bar.Infinity;',
+		'const foo = infinity;',
+		'const foo = "Infinity";',
+		'const foo = "-Infinity";',
+		// Shadowed
+		outdent`
+			function foo () {
+				const Infinity = 2
+				return Infinity
+			}
+		`,
+		'const {Infinity} = {};',
+		'function Infinity() {}',
+		'class Infinity {}',
+		'class Foo { Infinity(){}}',
+		{
+			code: 'const foo = Infinity;',
+			options: [{checkInfinity: false}]
+		},
+		{
+			code: 'const foo = -Infinity;',
+			options: [{checkInfinity: false}]
+		}
 	],
 	invalid: [
 		{
@@ -250,3 +282,29 @@ test.typescript({
 	],
 	invalid: []
 });
+
+test.visualize([
+	'const foo = Infinity;',
+	'if (Number.isNaN(Infinity)) {}',
+	'if (Object.is(foo, Infinity)) {}',
+	'const foo = bar[Infinity];',
+	'const foo = {Infinity};',
+	'const foo = {Infinity: Infinity};',
+	'const foo = {Infinity: -Infinity};',
+	'const {foo = Infinity} = {};',
+	'const {foo = -Infinity} = {};',
+	'const foo = Infinity.toString();',
+	'const foo = -Infinity.toString();',
+	'const foo = (-Infinity).toString();',
+	'const foo = +Infinity;',
+	'const foo = ++Infinity;',
+	'const foo = +-Infinity;',
+	'const foo = -Infinity;',
+	'const foo = --Infinity;',
+	'const foo = -(-Infinity);',
+	'const foo = -(--Infinity);',
+	'const foo = 1 - Infinity;',
+	'const foo = 1 - -Infinity;',
+	'const isPositiveZero = value => value === 0 && 1 / value === Infinity;',
+	'const isNegativeZero = value => value === 0 && 1 / value === -Infinity;'
+]);