diff options
Diffstat (limited to 'tools/eslint/lib/rules/no-self-assign.js')
| -rw-r--r-- | tools/eslint/lib/rules/no-self-assign.js | 109 |
1 files changed, 94 insertions, 15 deletions
diff --git a/tools/eslint/lib/rules/no-self-assign.js b/tools/eslint/lib/rules/no-self-assign.js index e3dc35e81e..bfc0241664 100644 --- a/tools/eslint/lib/rules/no-self-assign.js +++ b/tools/eslint/lib/rules/no-self-assign.js @@ -6,9 +6,66 @@ "use strict"; //------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +const astUtils = require("../ast-utils"); + +//------------------------------------------------------------------------------ // Helpers //------------------------------------------------------------------------------ +const SPACES = /\s+/g; + +/** + * Checks whether the property of 2 given member expression nodes are the same + * property or not. + * + * @param {ASTNode} left - A member expression node to check. + * @param {ASTNode} right - Another member expression node to check. + * @returns {boolean} `true` if the member expressions have the same property. + */ +function isSameProperty(left, right) { + if (left.property.type === "Identifier" && + left.property.type === right.property.type && + left.property.name === right.property.name && + left.computed === right.computed + ) { + return true; + } + + const lname = astUtils.getStaticPropertyName(left); + const rname = astUtils.getStaticPropertyName(right); + + return lname !== null && lname === rname; +} + +/** + * Checks whether 2 given member expression nodes are the reference to the same + * property or not. + * + * @param {ASTNode} left - A member expression node to check. + * @param {ASTNode} right - Another member expression node to check. + * @returns {boolean} `true` if the member expressions are the reference to the + * same property or not. + */ +function isSameMember(left, right) { + if (!isSameProperty(left, right)) { + return false; + } + + const lobj = left.object; + const robj = right.object; + + if (lobj.type !== robj.type) { + return false; + } + if (lobj.type === "MemberExpression") { + return isSameMember(lobj, robj); + } + return lobj.type === "Identifier" && lobj.name === robj.name; +} + /** * Traverses 2 Pattern nodes in parallel, then reports self-assignments. * @@ -16,12 +73,11 @@ * a Property. * @param {ASTNode|null} right - A right node to traverse. This is a Pattern or * a Property. + * @param {boolean} props - The flag to check member expressions as well. * @param {Function} report - A callback function to report. * @returns {void} */ -function eachSelfAssignment(left, right, report) { - let i, j; - +function eachSelfAssignment(left, right, props, report) { if (!left || !right) { // do nothing @@ -35,12 +91,12 @@ function eachSelfAssignment(left, right, report) { left.type === "ArrayPattern" && right.type === "ArrayExpression" ) { - let end = Math.min(left.elements.length, right.elements.length); + const end = Math.min(left.elements.length, right.elements.length); - for (i = 0; i < end; ++i) { - let rightElement = right.elements[i]; + for (let i = 0; i < end; ++i) { + const rightElement = right.elements[i]; - eachSelfAssignment(left.elements[i], rightElement, report); + eachSelfAssignment(left.elements[i], rightElement, props, report); // After a spread element, those indices are unknown. if (rightElement && rightElement.type === "SpreadElement") { @@ -51,7 +107,7 @@ function eachSelfAssignment(left, right, report) { left.type === "RestElement" && right.type === "SpreadElement" ) { - eachSelfAssignment(left.argument, right.argument, report); + eachSelfAssignment(left.argument, right.argument, props, report); } else if ( left.type === "ObjectPattern" && right.type === "ObjectExpression" && @@ -62,18 +118,19 @@ function eachSelfAssignment(left, right, report) { // It's possible to overwrite properties followed by it. let startJ = 0; - for (i = right.properties.length - 1; i >= 0; --i) { + for (let i = right.properties.length - 1; i >= 0; --i) { if (right.properties[i].type === "ExperimentalSpreadProperty") { startJ = i + 1; break; } } - for (i = 0; i < left.properties.length; ++i) { - for (j = startJ; j < right.properties.length; ++j) { + for (let i = 0; i < left.properties.length; ++i) { + for (let j = startJ; j < right.properties.length; ++j) { eachSelfAssignment( left.properties[i], right.properties[j], + props, report ); } @@ -87,7 +144,14 @@ function eachSelfAssignment(left, right, report) { !right.method && left.key.name === right.key.name ) { - eachSelfAssignment(left.value, right.value, report); + eachSelfAssignment(left.value, right.value, props, report); + } else if ( + props && + left.type === "MemberExpression" && + right.type === "MemberExpression" && + isSameMember(left, right) + ) { + report(right); } } @@ -103,10 +167,23 @@ module.exports = { recommended: true }, - schema: [] + schema: [ + { + type: "object", + properties: { + props: { + type: "boolean" + } + }, + additionalProperties: false + } + ] }, create: function(context) { + const sourceCode = context.getSourceCode(); + const options = context.options[0]; + const props = Boolean(options && options.props); /** * Reports a given node as self assignments. @@ -118,14 +195,16 @@ module.exports = { context.report({ node: node, message: "'{{name}}' is assigned to itself.", - data: node + data: { + name: sourceCode.getText(node).replace(SPACES, "") + } }); } return { AssignmentExpression: function(node) { if (node.operator === "=") { - eachSelfAssignment(node.left, node.right, report); + eachSelfAssignment(node.left, node.right, props, report); } } }; |