no-zero-fractions: Handle numeric separators, fix missing parentheses, improve report location (#1238)

Author: fisker

docs/rules/no-zero-fractions.md

@@ -4,27 +4,58 @@ There is no difference in JavaScript between, for example, `1`, `1.0` and `1.`,
 
 This rule is fixable.
 
-
 ## Fail
 
 ```js
 const foo = 1.0;
+```
+
+```js
 const foo = -1.0;
-const foo = 123123123.0;
+```
+
+```js
+const foo = 123_456.000_000;
+```
+
+```js
 const foo = 1.;
+```
+
+```js
 const foo = 123.111000000;
-const foo = 123.00e20;
 ```
 
+```js
+const foo = 123.00e20;
+```
 
 ## Pass
 
 ```js
 const foo = 1;
+```
+
+```js
 const foo = -1;
-const foo = 123123123;
+```
+
+```js
+const foo = 123456;
+```
+
+```js
 const foo = 1.1;
+```
+
+```js
 const foo = -1.1;
-const foo = 123123123.4;
+```
+
+```js
+const foo = 123.456;
+```
+
+```js
 const foo = 1e3;
 ```

rules/no-zero-fractions.js

@@ -1,5 +1,8 @@
 'use strict';
+const {isParenthesized} = require('eslint-utils');
 const getDocumentationUrl = require('./utils/get-documentation-url');
+const needsSemicolon = require('./utils/needs-semicolon');
+const {isNumber, isDecimalInteger} = require('./utils/numeric');
 
 const MESSAGE_ZERO_FRACTION = 'zero-fraction';
 const MESSAGE_DANGLING_DOT = 'dangling-dot';
@@ -8,45 +11,54 @@ const messages = {
 	[MESSAGE_DANGLING_DOT]: 'Don\'t use a dangling dot in the number.'
 };
 
-// Groups:
-// 1. Integer part.
-// 2. Dangling dot or dot with zeroes.
-// 3. Dot with digits except last zeroes.
-// 4. Scientific notation.
-const RE_DANGLINGDOT_OR_ZERO_FRACTIONS = /^(?<integerPart>[+-]?\d*)(?:(?<dotAndZeroes>\.0*)|(?<dotAndDigits>\.\d*[1-9])0+)(?<scientificNotationSuffix>e[+-]?\d+)?$/;
-
 const create = context => {
 	return {
 		Literal: node => {
-			if (typeof node.value !== 'number') {
+			if (!isNumber(node)) {
 				return;
 			}
 
-			const match = RE_DANGLINGDOT_OR_ZERO_FRACTIONS.exec(node.raw);
-			if (match === null) {
+			// Legacy octal number `0777` and prefixed number `0o1234` cannot have a dot.
+			const {raw} = node;
+			const match = raw.match(/^(?<before>[\d_]*)(?<dotAndFractions>\.[\d_]*)(?<after>.*)$/);
+			if (!match) {
 				return;
 			}
 
-			const {
-				integerPart,
-				dotAndZeroes,
-				dotAndDigits,
-				scientificNotationSuffix
-			} = match.groups;
+			const {before, dotAndFractions, after} = match.groups;
+			const formatted = before + dotAndFractions.replace(/[.0_]+$/g, '') + after;
 
-			const isDanglingDot = dotAndZeroes === '.';
+			if (formatted === raw) {
+				return;
+			}
 
+			const isDanglingDot = dotAndFractions === '.';
+			// End of fractions
+			const end = node.range[0] + before.length + dotAndFractions.length;
+			const start = end - (raw.length - formatted.length);
+			const sourceCode = context.getSourceCode();
 			context.report({
-				node,
+				loc: {
+					start: sourceCode.getLocFromIndex(start),
+					end: sourceCode.getLocFromIndex(end)
+				},
 				messageId: isDanglingDot ? MESSAGE_DANGLING_DOT : MESSAGE_ZERO_FRACTION,
 				fix: fixer => {
-					let wantedString = dotAndZeroes === undefined ? integerPart + dotAndDigits : integerPart;
+					let fixed = formatted;
+					if (
+						node.parent.type === 'MemberExpression' &&
+						node.parent.object === node &&
+						isDecimalInteger(formatted) &&
+						!isParenthesized(node, sourceCode)
+					) {
+						fixed = `(${fixed})`;
 
-					if (scientificNotationSuffix !== undefined) {
-						wantedString += scientificNotationSuffix;
+						if (needsSemicolon(sourceCode.getTokenBefore(node), sourceCode, fixed)) {
+							fixed = `;${fixed}`;
+						}
 					}
 
-					return fixer.replaceText(node, wantedString);
+					return fixer.replaceText(node, fixed);
 				}
 			});
 		}

rules/numeric-separators-style.js

@@ -35,7 +35,7 @@ function addSeparatorFromLeft(value, options) {
 }
 
 function formatNumber(value, options) {
-	const {integer, dot, fractional} = numeric.parseFloat(value);
+	const {integer, dot, fractional} = numeric.parseFloatNumber(value);
 	return addSeparator(integer, options) + dot + addSeparatorFromLeft(fractional, options);
 }
 
@@ -99,7 +99,7 @@ const create = context => {
 
 	return {
 		Literal: node => {
-			if (!numeric.isNumberic(node) || numeric.isLegacyOctal(node)) {
+			if (!numeric.isNumeric(node) || numeric.isLegacyOctal(node)) {
 				return;
 			}
 

rules/utils/numeric.js

@@ -3,11 +3,12 @@
 // Determine whether this node is a decimal integer literal.
 // Copied from https://github.com/eslint/eslint/blob/cc4871369645c3409dc56ded7a555af8a9f63d51/lib/rules/utils/ast-utils.js#L1237
 const DECIMAL_INTEGER_PATTERN = /^(?:0|0[0-7]*[89]\d*|[1-9](?:_?\d)*)$/u;
-const isDecimalInteger = node => isNumber(node) && DECIMAL_INTEGER_PATTERN.test(node.raw);
+const isDecimalInteger = text => DECIMAL_INTEGER_PATTERN.test(text);
+const isDecimalIntegerNode = node => isNumber(node) && isDecimalInteger(node.raw);
 
 const isNumber = node => typeof node.value === 'number';
 const isBigInt = node => Boolean(node.bigint);
-const isNumberic = node => isNumber(node) || isBigInt(node);
+const isNumeric = node => isNumber(node) || isBigInt(node);
 const isLegacyOctal = node => isNumber(node) && /^0\d+$/.test(node.raw);
 
 function getPrefix(text) {
@@ -28,17 +29,27 @@ function parseNumber(text) {
 		mark = '',
 		sign = '',
 		power = ''
-	} = text.match(/^(?<number>.*?)(?:(?<mark>e)(?<sign>[+-])?(?<power>\d+))?$/i).groups;
+	} = text.match(/^(?<number>[\d._]*?)(?:(?<mark>[Ee])(?<sign>[+-])?(?<power>[\d_]+))?$/).groups;
 
 	return {number, mark, sign, power};
 }
 
-function parseFloat(text) {
+function parseFloatNumber(text) {
 	const parts = text.split('.');
 	const [integer, fractional = ''] = parts;
 	const dot = parts.length === 2 ? '.' : '';
 
 	return {integer, dot, fractional};
 }
 
-module.exports = {isNumber, isBigInt, isNumberic, isLegacyOctal, getPrefix, parseNumber, parseFloat, isDecimalInteger};
+module.exports = {
+	isDecimalIntegerNode,
+	isDecimalInteger,
+	isNumber,
+	isBigInt,
+	isNumeric,
+	isLegacyOctal,
+	getPrefix,
+	parseNumber,
+	parseFloatNumber
+};

rules/utils/should-add-parentheses-to-member-expression-object.js

@@ -1,7 +1,7 @@
 'use strict';
 
 const isNewExpressionWithParentheses = require('./is-new-expression-with-parentheses');
-const {isDecimalInteger} = require('./numeric');
+const {isDecimalIntegerNode} = require('./numeric');
 
 /**
 Check if parentheses should to be added to a `node` when it's used as an `object` of `MemberExpression`.
@@ -24,7 +24,7 @@ function shouldAddParenthesesToMemberExpressionObject(node, sourceCode) {
 			return !isNewExpressionWithParentheses(node, sourceCode);
 		case 'Literal': {
 			/* istanbul ignore next */
-			if (isDecimalInteger(node)) {
+			if (isDecimalIntegerNode(node)) {
 				return true;
 			}