explicit-length-check: Ignore .length || number (#1977)

sindresorhus · May 18, 2023 · b9b8794 · b9b8794
1 parent 2907805
commit b9b8794
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Showing 2 changed files with 30 additions and 2 deletions.
diff --git a/rules/explicit-length-check.js b/rules/explicit-length-check.js
@@ -4,7 +4,7 @@ const {checkVueTemplate} = require('./utils/rule.js');
 const isLogicalExpression = require('./utils/is-logical-expression.js');
 const {isBooleanNode, getBooleanAncestor} = require('./utils/boolean.js');
 const {fixSpaceAroundKeyword} = require('./fix/index.js');
-const {isLiteral, isMemberExpression} = require('./ast/index.js');
+const {isLiteral, isMemberExpression, isNumberLiteral} = require('./ast/index.js');
 
 const TYPE_NON_ZERO = 'non-zero';
 const TYPE_ZERO = 'zero';
@@ -90,6 +90,15 @@ function getLengthCheckNode(node) {
 	return {};
 }
 
+function isNodeValueNumber(node, context) {
+	if (isNumberLiteral(node)) {
+		return true;
+	}
+
+	const staticValue = getStaticValue(node, context.sourceCode.getScope(node));
+	return staticValue && typeof staticValue.value === 'number';
+}
+
 function create(context) {
 	const options = {
 		'non-zero': 'greater-than',
@@ -171,7 +180,13 @@ function create(context) {
 				if (isBooleanNode(ancestor)) {
 					isZeroLengthCheck = isNegative;
 					node = ancestor;
-				} else if (isLogicalExpression(lengthNode.parent)) {
+				} else if (
+					isLogicalExpression(lengthNode.parent)
+					&& !(
+						lengthNode.parent.operator === '||'
+						&& isNodeValueNumber(lengthNode.parent.right, context)
+					)
+				) {
 					isZeroLengthCheck = isNegative;
 					node = lengthNode;
 					autoFix = false;

diff --git a/test/explicit-length-check.mjs b/test/explicit-length-check.mjs
@@ -103,13 +103,26 @@ test({
 		'const foo = { length: 1.5 }; if (foo.length) {}', // Array lengths must be integers
 		'const foo = { length: NaN }; if (foo.length) {}', // Array lengths cannot be NaN
 		'const foo = { length: Infinity }; if (foo.length) {}', // Array lengths cannot be Infinity
+		// Logical OR
+		'const x = foo.length || 2',
+		'const A_NUMBER = 2; const x = foo.length || A_NUMBER',
 	],
 	invalid: [
 		suggestionCase({
 			code: 'const x = foo.length || bar()',
 			output: 'const x = foo.length > 0 || bar()',
 			desc: 'Replace `.length` with `.length > 0`.',
 		}),
+		suggestionCase({
+			code: 'const x = foo.length || unknown',
+			output: 'const x = foo.length > 0 || unknown',
+			desc: 'Replace `.length` with `.length > 0`.',
+		}),
+		suggestionCase({
+			code: 'const NON_NUMBER = "2"; const x = foo.length || NON_NUMBER',
+			output: 'const NON_NUMBER = "2"; const x = foo.length > 0 || NON_NUMBER',
+			desc: 'Replace `.length` with `.length > 0`.',
+		}),
 		suggestionCase({
 			code: 'const x = foo.length || bar()',
 			output: 'const x = foo.length !== 0 || bar()',