Don't consider ?? operator LogicExpression as a boolean value node (

#986)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

rules/explicit-length-check.js

@@ -2,6 +2,7 @@
 const {isParenthesized} = require('eslint-utils');
 const getDocumentationUrl = require('./utils/get-documentation-url');
 const isLiteralValue = require('./utils/is-literal-value');
+const isLogicalExpression = require('./utils/is-logical-expression');
 const {isBooleanNode, getBooleanAncestor} = require('./utils/boolean');
 
 const TYPE_NON_ZERO = 'non-zero';
@@ -165,7 +166,7 @@ function create(context) {
 				if (isBooleanNode(ancestor)) {
 					isZeroLengthCheck = isNegative;
 					node = ancestor;
-				} else if (lengthNode.parent.type === 'LogicalExpression') {
+				} else if (isLogicalExpression(lengthNode.parent)) {
 					isZeroLengthCheck = isNegative;
 					node = lengthNode;
 					autoFix = false;

rules/utils/boolean.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const isLogicalExpression = require('./is-logical-expression');
+
 const isLogicNot = node =>
 	node &&
 	node.type === 'UnaryExpression' &&
@@ -48,7 +50,7 @@ function isBooleanNode(node) {
 		return true;
 	}
 
-	if (parent.type === 'LogicalExpression') {
+	if (isLogicalExpression(parent)) {
 		return isBooleanNode(parent);
 	}
 

rules/utils/is-logical-expression.js

@@ -0,0 +1,17 @@
+'use strict';
+
+/**
+Check if the given node is a true logical expression or not.
+
+The three binary expressions logical-or (`||`), logical-and (`&&`), and coalesce (`??`) are known as `ShortCircuitExpression`, but ESTree represents these by the `LogicalExpression` node type. This function rejects coalesce expressions of `LogicalExpression` node type.
+
+@param {Node} node - The node to check.
+@returns {boolean} `true` if the node is `&&` or `||`.
+@see https://tc39.es/ecma262/#prod-ShortCircuitExpression
+*/
+const isLogicalExpression = node =>
+	node &&
+	node.type === 'LogicalExpression' &&
+	(node.operator === '&&' || node.operator === '||');
+
+module.exports = isLogicalExpression;

test/explicit-length-check.js

@@ -58,6 +58,8 @@ test({
 		'const x = Boolean(foo.length, foo.length)',
 		'const x = new Boolean(foo.length)',
 		'const x = NotBoolean(foo.length)',
+		'const length = foo.length ?? 0',
+		'if (foo.length ?? bar) {}',
 
 		// Checking 'non-zero'
 		'if (foo.length > 0) {}',

test/prefer-array-some.js

@@ -25,6 +25,7 @@ test({
 		// Not `boolean`
 		'const bar = foo.find(fn)',
 		'const bar = foo.find(fn) || baz',
+		'if (foo.find(fn) ?? bar) {}',
 
 		// Not matched `CallExpression`
 		...[