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Diffstat (limited to 'tools/node_modules/eslint/lib/rules/no-this-before-super.js')
| -rw-r--r-- | tools/node_modules/eslint/lib/rules/no-this-before-super.js | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-this-before-super.js b/tools/node_modules/eslint/lib/rules/no-this-before-super.js new file mode 100644 index 0000000000..2a686ac72e --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/no-this-before-super.js @@ -0,0 +1,299 @@ +/** + * @fileoverview A rule to disallow using `this`/`super` before `super()`. + * @author Toru Nagashima + */ + +"use strict"; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +const astUtils = require("../ast-utils"); + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +/** + * Checks whether or not a given node is a constructor. + * @param {ASTNode} node - A node to check. This node type is one of + * `Program`, `FunctionDeclaration`, `FunctionExpression`, and + * `ArrowFunctionExpression`. + * @returns {boolean} `true` if the node is a constructor. + */ +function isConstructorFunction(node) { + return ( + node.type === "FunctionExpression" && + node.parent.type === "MethodDefinition" && + node.parent.kind === "constructor" + ); +} + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + docs: { + description: "disallow `this`/`super` before calling `super()` in constructors", + category: "ECMAScript 6", + recommended: true + }, + + schema: [] + }, + + create(context) { + + /* + * Information for each constructor. + * - upper: Information of the upper constructor. + * - hasExtends: A flag which shows whether the owner class has a valid + * `extends` part. + * - scope: The scope of the owner class. + * - codePath: The code path of this constructor. + */ + let funcInfo = null; + + /* + * Information for each code path segment. + * Each key is the id of a code path segment. + * Each value is an object: + * - superCalled: The flag which shows `super()` called in all code paths. + * - invalidNodes: The array of invalid ThisExpression and Super nodes. + */ + let segInfoMap = Object.create(null); + + /** + * Gets whether or not `super()` is called in a given code path segment. + * @param {CodePathSegment} segment - A code path segment to get. + * @returns {boolean} `true` if `super()` is called. + */ + function isCalled(segment) { + return !segment.reachable || segInfoMap[segment.id].superCalled; + } + + /** + * Checks whether or not this is in a constructor. + * @returns {boolean} `true` if this is in a constructor. + */ + function isInConstructorOfDerivedClass() { + return Boolean(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends); + } + + /** + * Checks whether or not this is before `super()` is called. + * @returns {boolean} `true` if this is before `super()` is called. + */ + function isBeforeCallOfSuper() { + return ( + isInConstructorOfDerivedClass() && + !funcInfo.codePath.currentSegments.every(isCalled) + ); + } + + /** + * Sets a given node as invalid. + * @param {ASTNode} node - A node to set as invalid. This is one of + * a ThisExpression and a Super. + * @returns {void} + */ + function setInvalid(node) { + const segments = funcInfo.codePath.currentSegments; + + for (let i = 0; i < segments.length; ++i) { + const segment = segments[i]; + + if (segment.reachable) { + segInfoMap[segment.id].invalidNodes.push(node); + } + } + } + + /** + * Sets the current segment as `super` was called. + * @returns {void} + */ + function setSuperCalled() { + const segments = funcInfo.codePath.currentSegments; + + for (let i = 0; i < segments.length; ++i) { + const segment = segments[i]; + + if (segment.reachable) { + segInfoMap[segment.id].superCalled = true; + } + } + } + + return { + + /** + * Adds information of a constructor into the stack. + * @param {CodePath} codePath - A code path which was started. + * @param {ASTNode} node - The current node. + * @returns {void} + */ + onCodePathStart(codePath, node) { + if (isConstructorFunction(node)) { + + // Class > ClassBody > MethodDefinition > FunctionExpression + const classNode = node.parent.parent.parent; + + funcInfo = { + upper: funcInfo, + isConstructor: true, + hasExtends: Boolean( + classNode.superClass && + !astUtils.isNullOrUndefined(classNode.superClass) + ), + codePath + }; + } else { + funcInfo = { + upper: funcInfo, + isConstructor: false, + hasExtends: false, + codePath + }; + } + }, + + /** + * Removes the top of stack item. + * + * And this treverses all segments of this code path then reports every + * invalid node. + * + * @param {CodePath} codePath - A code path which was ended. + * @param {ASTNode} node - The current node. + * @returns {void} + */ + onCodePathEnd(codePath) { + const isDerivedClass = funcInfo.hasExtends; + + funcInfo = funcInfo.upper; + if (!isDerivedClass) { + return; + } + + codePath.traverseSegments((segment, controller) => { + const info = segInfoMap[segment.id]; + + for (let i = 0; i < info.invalidNodes.length; ++i) { + const invalidNode = info.invalidNodes[i]; + + context.report({ + message: "'{{kind}}' is not allowed before 'super()'.", + node: invalidNode, + data: { + kind: invalidNode.type === "Super" ? "super" : "this" + } + }); + } + + if (info.superCalled) { + controller.skip(); + } + }); + }, + + /** + * Initialize information of a given code path segment. + * @param {CodePathSegment} segment - A code path segment to initialize. + * @returns {void} + */ + onCodePathSegmentStart(segment) { + if (!isInConstructorOfDerivedClass()) { + return; + } + + // Initialize info. + segInfoMap[segment.id] = { + superCalled: ( + segment.prevSegments.length > 0 && + segment.prevSegments.every(isCalled) + ), + invalidNodes: [] + }; + }, + + /** + * Update information of the code path segment when a code path was + * looped. + * @param {CodePathSegment} fromSegment - The code path segment of the + * end of a loop. + * @param {CodePathSegment} toSegment - A code path segment of the head + * of a loop. + * @returns {void} + */ + onCodePathSegmentLoop(fromSegment, toSegment) { + if (!isInConstructorOfDerivedClass()) { + return; + } + + // Update information inside of the loop. + funcInfo.codePath.traverseSegments( + { first: toSegment, last: fromSegment }, + (segment, controller) => { + const info = segInfoMap[segment.id]; + + if (info.superCalled) { + info.invalidNodes = []; + controller.skip(); + } else if ( + segment.prevSegments.length > 0 && + segment.prevSegments.every(isCalled) + ) { + info.superCalled = true; + info.invalidNodes = []; + } + } + ); + }, + + /** + * Reports if this is before `super()`. + * @param {ASTNode} node - A target node. + * @returns {void} + */ + ThisExpression(node) { + if (isBeforeCallOfSuper()) { + setInvalid(node); + } + }, + + /** + * Reports if this is before `super()`. + * @param {ASTNode} node - A target node. + * @returns {void} + */ + Super(node) { + if (!astUtils.isCallee(node) && isBeforeCallOfSuper()) { + setInvalid(node); + } + }, + + /** + * Marks `super()` called. + * @param {ASTNode} node - A target node. + * @returns {void} + */ + "CallExpression:exit"(node) { + if (node.callee.type === "Super" && isBeforeCallOfSuper()) { + setSuperCalled(); + } + }, + + /** + * Resets state. + * @returns {void} + */ + "Program:exit"() { + segInfoMap = Object.create(null); + } + }; + } +}; |