Reuse utilities (#2798)

Author: fisker

rules/ast/index.js

@@ -18,6 +18,7 @@ export {default as isArrowFunctionBody} from './is-arrow-function-body.js';
 export {default as isDirective} from './is-directive.js';
 export {default as isEmptyNode} from './is-empty-node.js';
 export {default as isEmptyArrayExpression} from './is-empty-array-expression.js';
+export {default as isEmptyObjectExpression} from './is-empty-object-expression.js';
 export {default as isExpressionStatement} from './is-expression-statement.js';
 export {default as isFunction} from './is-function.js';
 export {default as isMemberExpression} from './is-member-expression.js';

rules/ast/is-empty-object-expression.js

@@ -0,0 +1,5 @@
+const isEmptyArrayExpression = node =>
+	node.type === 'ObjectExpression'
+	&& node.properties.length === 0;
+
+export default isEmptyArrayExpression;

rules/consistent-empty-array-spread.js

@@ -1,18 +1,14 @@
 import {getStaticValue} from '@eslint-community/eslint-utils';
+import {
+	isEmptyArrayExpression,
+	isEmptyStringLiteral,
+} from './ast/index.js';
 
 const MESSAGE_ID = 'consistent-empty-array-spread';
 const messages = {
 	[MESSAGE_ID]: 'Prefer using empty {{replacementDescription}} since the {{anotherNodePosition}} is {{anotherNodeDescription}}.',
 };
 
-const isEmptyArrayExpression = node =>
-	node.type === 'ArrayExpression'
-	&& node.elements.length === 0;
-
-const isEmptyStringLiteral = node =>
-	node.type === 'Literal'
-	&& node.value === '';
-
 const isString = (node, context) => {
 	const staticValueResult = getStaticValue(node, context.sourceCode.getScope(node));
 	return typeof staticValueResult?.value === 'string';

rules/no-useless-fallback-in-spread.js

@@ -1,5 +1,6 @@
 import {isParenthesized, getParenthesizedRange} from './utils/index.js';
 import {removeParentheses} from './fix/index.js';
+import {isEmptyObjectExpression} from './ast/index.js';
 
 const MESSAGE_ID = 'no-useless-fallback-in-spread';
 const messages = {
@@ -10,7 +11,7 @@ const messages = {
 const create = context => {
 	context.on('ObjectExpression', node => {
 		if (!(
-			node.properties.length === 0
+			isEmptyObjectExpression(node)
 			&& node.parent.type === 'LogicalExpression'
 			&& node.parent.right === node
 			&& (node.parent.operator === '||' || node.parent.operator === '??')

rules/no-useless-spread.js

@@ -2,7 +2,13 @@ import {isCommaToken} from '@eslint-community/eslint-utils';
 import typedArray from './shared/typed-array.js';
 import {removeParentheses, fixSpaceAroundKeyword, addParenthesizesToReturnOrThrowExpression} from './fix/index.js';
 import {isParenthesized, isOnSameLine} from './utils/index.js';
-import {isNewExpression, isMethodCall, isCallOrNewExpression} from './ast/index.js';
+import {
+	isNewExpression,
+	isMethodCall,
+	isCallOrNewExpression,
+	isEmptyArrayExpression,
+	isEmptyObjectExpression,
+} from './ast/index.js';
 
 const SPREAD_IN_LIST = 'spread-in-list';
 const ITERABLE_TO_ARRAY = 'iterable-to-array';
@@ -179,10 +185,7 @@ const create = context => {
 
 				// `[...[], 1]`
 				//        ^
-				if (
-					(node.type === 'ArrayExpression' && node.elements.length === 0)
-					|| (node.type === 'ObjectExpression' && node.properties.length === 0)
-				) {
+				if (isEmptyArrayExpression(node) || isEmptyObjectExpression(node)) {
 					const nextToken = sourceCode.getTokenAfter(spreadElement);
 					if (isCommaToken(nextToken)) {
 						yield fixer.remove(nextToken);

rules/prefer-negative-index.js

@@ -1,6 +1,6 @@
 import {getNegativeIndexLengthNode, removeLengthNode} from './shared/negative-index.js';
 import typedArray from './shared/typed-array.js';
-import {isLiteral} from './ast/index.js';
+import {isEmptyArrayExpression, isLiteral} from './ast/index.js';
 
 const MESSAGE_ID = 'prefer-negative-index';
 const messages = {
@@ -115,10 +115,7 @@ function parse(node) {
 
 	if (
 		// `[].{slice,splice,toSpliced,at,with}`
-		(
-			parentCallee.type === 'ArrayExpression'
-			&& parentCallee.elements.length === 0
-		)
+		isEmptyArrayExpression(parentCallee)
 		// `''.slice`
 		|| (
 			method === 'slice'

rules/prefer-object-from-entries.js

@@ -1,5 +1,5 @@
 import {isCommaToken, isArrowToken, isClosingParenToken} from '@eslint-community/eslint-utils';
-import {isMethodCall, isLiteral} from './ast/index.js';
+import {isMethodCall, isLiteral, isEmptyObjectExpression} from './ast/index.js';
 import {removeParentheses} from './fix/index.js';
 import {
 	getParentheses,
@@ -18,7 +18,7 @@ const messages = {
 
 const isEmptyObject = node =>
 	// `{}`
-	(node.type === 'ObjectExpression' && node.properties.length === 0)
+	isEmptyObjectExpression(node)
 	// `Object.create(null)`
 	|| (
 		isMethodCall(node, {

rules/prefer-prototype-methods.js

@@ -1,6 +1,11 @@
 import {getPropertyName, ReferenceTracker} from '@eslint-community/eslint-utils';
 import {fixSpaceAroundKeyword} from './fix/index.js';
-import {isMemberExpression, isMethodCall} from './ast/index.js';
+import {
+	isEmptyArrayExpression,
+	isEmptyObjectExpression,
+	isMemberExpression,
+	isMethodCall,
+} from './ast/index.js';
 
 const messages = {
 	'known-method': 'Prefer using `{{constructorName}}.prototype.{{methodName}}`.',
@@ -37,10 +42,7 @@ function getConstructorAndMethodName(methodNode, {context, globalReferences}) {
 
 	const objectNode = methodNode.object;
 
-	if (!(
-		(objectNode.type === 'ArrayExpression' && objectNode.elements.length === 0)
-		|| (objectNode.type === 'ObjectExpression' && objectNode.properties.length === 0)
-	)) {
+	if (!(isEmptyArrayExpression(objectNode) || isEmptyObjectExpression(objectNode))) {
 		return;
 	}
 

rules/require-module-attributes.js

@@ -1,4 +1,5 @@
 import {isCommaToken} from '@eslint-community/eslint-utils';
+import {isEmptyObjectExpression} from './ast/index.js';
 import {removeObjectProperty} from './fix/index.js';
 import {getParentheses} from './utils/index.js';
 
@@ -70,8 +71,7 @@ const create = context => {
 						&& property.key.value === 'with'
 					)
 				)
-				&& property.value.type === 'ObjectExpression'
-				&& property.value.properties.length === 0,
+				&& isEmptyObjectExpression(property.value),
 		);
 
 		const nodeToRemove = optionsNode.properties.length === 0 || (emptyWithProperty && optionsNode.properties.length === 1)

rules/utils/array-or-object-prototype-property.js

@@ -1,4 +1,8 @@
-import {isMemberExpression} from '../ast/index.js';
+import {
+	isMemberExpression,
+	isEmptyArrayExpression,
+	isEmptyObjectExpression,
+} from '../ast/index.js';
 
 /**
 @param {
@@ -39,17 +43,9 @@ function isPrototypeProperty(node, options) {
 			optional: false,
 		})
 		// `[].method`
-		|| (
-			object === 'Array'
-			&& objectNode.type === 'ArrayExpression'
-			&& objectNode.elements.length === 0
-		)
+		|| (object === 'Array' && isEmptyArrayExpression(objectNode))
 		// `{}.method`
-		|| (
-			object === 'Object'
-			&& objectNode.type === 'ObjectExpression'
-			&& objectNode.properties.length === 0
-		)
+		|| (object === 'Object' && isEmptyObjectExpression(objectNode))
 	);
 }