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Diffstat (limited to 'tools/node_modules/eslint/lib/rules/no-negated-condition.js')
-rw-r--r-- | tools/node_modules/eslint/lib/rules/no-negated-condition.js | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-negated-condition.js b/tools/node_modules/eslint/lib/rules/no-negated-condition.js new file mode 100644 index 0000000000..8ea8559ea1 --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/no-negated-condition.js @@ -0,0 +1,82 @@ +/** + * @fileoverview Rule to disallow a negated condition + * @author Alberto RodrÃguez + */ +"use strict"; + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + docs: { + description: "disallow negated conditions", + category: "Stylistic Issues", + recommended: false + }, + + schema: [] + }, + + create(context) { + + /** + * Determines if a given node is an if-else without a condition on the else + * @param {ASTNode} node The node to check. + * @returns {boolean} True if the node has an else without an if. + * @private + */ + function hasElseWithoutCondition(node) { + return node.alternate && node.alternate.type !== "IfStatement"; + } + + /** + * Determines if a given node is a negated unary expression + * @param {Object} test The test object to check. + * @returns {boolean} True if the node is a negated unary expression. + * @private + */ + function isNegatedUnaryExpression(test) { + return test.type === "UnaryExpression" && test.operator === "!"; + } + + /** + * Determines if a given node is a negated binary expression + * @param {Test} test The test to check. + * @returns {boolean} True if the node is a negated binary expression. + * @private + */ + function isNegatedBinaryExpression(test) { + return test.type === "BinaryExpression" && + (test.operator === "!=" || test.operator === "!=="); + } + + /** + * Determines if a given node has a negated if expression + * @param {ASTNode} node The node to check. + * @returns {boolean} True if the node has a negated if expression. + * @private + */ + function isNegatedIf(node) { + return isNegatedUnaryExpression(node.test) || isNegatedBinaryExpression(node.test); + } + + return { + IfStatement(node) { + if (!hasElseWithoutCondition(node)) { + return; + } + + if (isNegatedIf(node)) { + context.report({ node, message: "Unexpected negated condition." }); + } + }, + ConditionalExpression(node) { + if (isNegatedIf(node)) { + context.report({ node, message: "Unexpected negated condition." }); + } + } + }; + } +}; |