src/third_party/devtools/node_modules/eslint/lib/rules/constructor-super.js - cobalt - Git at Google

 /**
  * @fileoverview A rule to verify `super()` callings in constructor.
  * @author Toru Nagashima
  */

 "use strict";

 //------------------------------------------------------------------------------
 // Helpers
 //------------------------------------------------------------------------------

 /**
  * Checks whether a given code path segment is reachable or not.
  *
  * @param {CodePathSegment} segment - A code path segment to check.
  * @returns {boolean} `true` if the segment is reachable.
  */
 function isReachable(segment) {
     return segment.reachable;
 }

 /**
  * 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"
     );
 }

 /**
  * Checks whether a given node can be a constructor or not.
  *
  * @param {ASTNode} node - A node to check.
  * @returns {boolean} `true` if the node can be a constructor.
  */
 function isPossibleConstructor(node) {
     if (!node) {
         return false;
     }

     switch (node.type) {
         case "ClassExpression":
         case "FunctionExpression":
         case "ThisExpression":
         case "MemberExpression":
         case "CallExpression":
         case "NewExpression":
         case "YieldExpression":
         case "TaggedTemplateExpression":
         case "MetaProperty":
             return true;

         case "Identifier":
             return node.name !== "undefined";

         case "AssignmentExpression":
             return isPossibleConstructor(node.right);

         case "LogicalExpression":
             return (
                 isPossibleConstructor(node.left) ||
                 isPossibleConstructor(node.right)
             );

         case "ConditionalExpression":
             return (
                 isPossibleConstructor(node.alternate) ||
                 isPossibleConstructor(node.consequent)
             );

         case "SequenceExpression": {
             const lastExpression = node.expressions[node.expressions.length - 1];

             return isPossibleConstructor(lastExpression);
         }

         default:
             return false;
     }
 }

 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------

 module.exports = {
     meta: {
         type: "problem",

         docs: {
             description: "require `super()` calls in constructors",
             category: "ECMAScript 6",
             recommended: true,
             url: "https://eslint.org/docs/rules/constructor-super"
         },

         schema: [],

         messages: {
             missingSome: "Lacked a call of 'super()' in some code paths.",
             missingAll: "Expected to call 'super()'.",

             duplicate: "Unexpected duplicate 'super()'.",
             badSuper: "Unexpected 'super()' because 'super' is not a constructor.",
             unexpected: "Unexpected 'super()'."
         }
     },

     create(context) {

         /*
          * {{hasExtends: boolean, scope: Scope, codePath: CodePath}[]}
          * Information for each constructor.
          * - upper:      Information of the upper constructor.
          * - hasExtends: A flag which shows whether own class has a valid `extends`
          *               part.
          * - scope:      The scope of own class.
          * - codePath:   The code path object of the constructor.
          */
         let funcInfo = null;

         /*
          * {Map<string, {calledInSomePaths: boolean, calledInEveryPaths: boolean}>}
          * Information for each code path segment.
          * - calledInSomePaths:  A flag of be called `super()` in some code paths.
          * - calledInEveryPaths: A flag of be called `super()` in all code paths.
          * - validNodes:
          */
         let segInfoMap = Object.create(null);

         /**
          * Gets the flag which shows `super()` is called in some paths.
          * @param {CodePathSegment} segment - A code path segment to get.
          * @returns {boolean} The flag which shows `super()` is called in some paths
          */
         function isCalledInSomePath(segment) {
             return segment.reachable && segInfoMap[segment.id].calledInSomePaths;
         }

         /**
          * Gets the flag which shows `super()` is called in all paths.
          * @param {CodePathSegment} segment - A code path segment to get.
          * @returns {boolean} The flag which shows `super()` is called in all paths.
          */
         function isCalledInEveryPath(segment) {

             /*
              * If specific segment is the looped segment of the current segment,
              * skip the segment.
              * If not skipped, this never becomes true after a loop.
              */
             if (segment.nextSegments.length === 1 &&
                 segment.nextSegments[0].isLoopedPrevSegment(segment)
             ) {
                 return true;
             }
             return segment.reachable && segInfoMap[segment.id].calledInEveryPaths;
         }

         return {

             /**
              * Stacks a constructor information.
              * @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;
                     const superClass = classNode.superClass;

                     funcInfo = {
                         upper: funcInfo,
                         isConstructor: true,
                         hasExtends: Boolean(superClass),
                         superIsConstructor: isPossibleConstructor(superClass),
                         codePath
                     };
                 } else {
                     funcInfo = {
                         upper: funcInfo,
                         isConstructor: false,
                         hasExtends: false,
                         superIsConstructor: false,
                         codePath
                     };
                 }
             },

             /**
              * Pops a constructor information.
              * And reports if `super()` lacked.
              * @param {CodePath} codePath - A code path which was ended.
              * @param {ASTNode} node - The current node.
              * @returns {void}
              */
             onCodePathEnd(codePath, node) {
                 const hasExtends = funcInfo.hasExtends;

                 // Pop.
                 funcInfo = funcInfo.upper;

                 if (!hasExtends) {
                     return;
                 }

                 // Reports if `super()` lacked.
                 const segments = codePath.returnedSegments;
                 const calledInEveryPaths = segments.every(isCalledInEveryPath);
                 const calledInSomePaths = segments.some(isCalledInSomePath);

                 if (!calledInEveryPaths) {
                     context.report({
                         messageId: calledInSomePaths
                             ? "missingSome"
                             : "missingAll",
                         node: node.parent
                     });
                 }
             },

             /**
              * Initialize information of a given code path segment.
              * @param {CodePathSegment} segment - A code path segment to initialize.
              * @returns {void}
              */
             onCodePathSegmentStart(segment) {
                 if (!(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends)) {
                     return;
                 }

                 // Initialize info.
                 const info = segInfoMap[segment.id] = {
                     calledInSomePaths: false,
                     calledInEveryPaths: false,
                     validNodes: []
                 };

                 // When there are previous segments, aggregates these.
                 const prevSegments = segment.prevSegments;

                 if (prevSegments.length > 0) {
                     info.calledInSomePaths = prevSegments.some(isCalledInSomePath);
                     info.calledInEveryPaths = prevSegments.every(isCalledInEveryPath);
                 }
             },

             /**
              * 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 (!(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends)) {
                     return;
                 }

                 // Update information inside of the loop.
                 const isRealLoop = toSegment.prevSegments.length >= 2;

                 funcInfo.codePath.traverseSegments(
                     { first: toSegment, last: fromSegment },
                     segment => {
                         const info = segInfoMap[segment.id];
                         const prevSegments = segment.prevSegments;

                         // Updates flags.
                         info.calledInSomePaths = prevSegments.some(isCalledInSomePath);
                         info.calledInEveryPaths = prevSegments.every(isCalledInEveryPath);

                         // If flags become true anew, reports the valid nodes.
                         if (info.calledInSomePaths || isRealLoop) {
                             const nodes = info.validNodes;

                             info.validNodes = [];

                             for (let i = 0; i < nodes.length; ++i) {
                                 const node = nodes[i];

                                 context.report({
                                     messageId: "duplicate",
                                     node
                                 });
                             }
                         }
                     }
                 );
             },

             /**
              * Checks for a call of `super()`.
              * @param {ASTNode} node - A CallExpression node to check.
              * @returns {void}
              */
             "CallExpression:exit"(node) {
                 if (!(funcInfo && funcInfo.isConstructor)) {
                     return;
                 }

                 // Skips except `super()`.
                 if (node.callee.type !== "Super") {
                     return;
                 }

                 // Reports if needed.
                 if (funcInfo.hasExtends) {
                     const segments = funcInfo.codePath.currentSegments;
                     let duplicate = false;
                     let info = null;

                     for (let i = 0; i < segments.length; ++i) {
                         const segment = segments[i];

                         if (segment.reachable) {
                             info = segInfoMap[segment.id];

                             duplicate = duplicate || info.calledInSomePaths;
                             info.calledInSomePaths = info.calledInEveryPaths = true;
                         }
                     }

                     if (info) {
                         if (duplicate) {
                             context.report({
                                 messageId: "duplicate",
                                 node
                             });
                         } else if (!funcInfo.superIsConstructor) {
                             context.report({
                                 messageId: "badSuper",
                                 node
                             });
                         } else {
                             info.validNodes.push(node);
                         }
                     }
                 } else if (funcInfo.codePath.currentSegments.some(isReachable)) {
                     context.report({
                         messageId: "unexpected",
                         node
                     });
                 }
             },

             /**
              * Set the mark to the returned path as `super()` was called.
              * @param {ASTNode} node - A ReturnStatement node to check.
              * @returns {void}
              */
             ReturnStatement(node) {
                 if (!(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends)) {
                     return;
                 }

                 // Skips if no argument.
                 if (!node.argument) {
                     return;
                 }

                 // Returning argument is a substitute of 'super()'.
                 const segments = funcInfo.codePath.currentSegments;

                 for (let i = 0; i < segments.length; ++i) {
                     const segment = segments[i];

                     if (segment.reachable) {
                         const info = segInfoMap[segment.id];

                         info.calledInSomePaths = info.calledInEveryPaths = true;
                     }
                 }
             },

             /**
              * Resets state.
              * @returns {void}
              */
             "Program:exit"() {
                 segInfoMap = Object.create(null);
             }
         };
     }
 };
	/**
	* @fileoverview A rule to verify `super()` callings in constructor.
	* @author Toru Nagashima
	*/

	"use strict";

	//------------------------------------------------------------------------------
	// Helpers
	//------------------------------------------------------------------------------

	/**
	* Checks whether a given code path segment is reachable or not.
	*
	* @param {CodePathSegment} segment - A code path segment to check.
	* @returns {boolean} `true` if the segment is reachable.
	*/
	function isReachable(segment) {
	return segment.reachable;
	}

	/**
	* 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"
	);
	}

	/**
	* Checks whether a given node can be a constructor or not.
	*
	* @param {ASTNode} node - A node to check.
	* @returns {boolean} `true` if the node can be a constructor.
	*/
	function isPossibleConstructor(node) {
	if (!node) {
	return false;
	}

	switch (node.type) {
	case "ClassExpression":
	case "FunctionExpression":
	case "ThisExpression":
	case "MemberExpression":
	case "CallExpression":
	case "NewExpression":
	case "YieldExpression":
	case "TaggedTemplateExpression":
	case "MetaProperty":
	return true;

	case "Identifier":
	return node.name !== "undefined";

	case "AssignmentExpression":
	return isPossibleConstructor(node.right);

	case "LogicalExpression":
	return (
	isPossibleConstructor(node.left) \|\|
	isPossibleConstructor(node.right)
	);

	case "ConditionalExpression":
	return (
	isPossibleConstructor(node.alternate) \|\|
	isPossibleConstructor(node.consequent)
	);

	case "SequenceExpression": {
	const lastExpression = node.expressions[node.expressions.length - 1];

	return isPossibleConstructor(lastExpression);
	}

	default:
	return false;
	}
	}

	//------------------------------------------------------------------------------
	// Rule Definition
	//------------------------------------------------------------------------------

	module.exports = {
	meta: {
	type: "problem",

	docs: {
	description: "require `super()` calls in constructors",
	category: "ECMAScript 6",
	recommended: true,
	url: "https://eslint.org/docs/rules/constructor-super"
	},

	schema: [],

	messages: {
	missingSome: "Lacked a call of 'super()' in some code paths.",
	missingAll: "Expected to call 'super()'.",

	duplicate: "Unexpected duplicate 'super()'.",
	badSuper: "Unexpected 'super()' because 'super' is not a constructor.",
	unexpected: "Unexpected 'super()'."
	}
	},

	create(context) {

	/*
	* {{hasExtends: boolean, scope: Scope, codePath: CodePath}[]}
	* Information for each constructor.
	* - upper: Information of the upper constructor.
	* - hasExtends: A flag which shows whether own class has a valid `extends`
	* part.
	* - scope: The scope of own class.
	* - codePath: The code path object of the constructor.
	*/
	let funcInfo = null;

	/*
	* {Map<string, {calledInSomePaths: boolean, calledInEveryPaths: boolean}>}
	* Information for each code path segment.
	* - calledInSomePaths: A flag of be called `super()` in some code paths.
	* - calledInEveryPaths: A flag of be called `super()` in all code paths.
	* - validNodes:
	*/
	let segInfoMap = Object.create(null);

	/**
	* Gets the flag which shows `super()` is called in some paths.
	* @param {CodePathSegment} segment - A code path segment to get.
	* @returns {boolean} The flag which shows `super()` is called in some paths
	*/
	function isCalledInSomePath(segment) {
	return segment.reachable && segInfoMap[segment.id].calledInSomePaths;
	}

	/**
	* Gets the flag which shows `super()` is called in all paths.
	* @param {CodePathSegment} segment - A code path segment to get.
	* @returns {boolean} The flag which shows `super()` is called in all paths.
	*/
	function isCalledInEveryPath(segment) {

	/*
	* If specific segment is the looped segment of the current segment,
	* skip the segment.
	* If not skipped, this never becomes true after a loop.
	*/
	if (segment.nextSegments.length === 1 &&
	segment.nextSegments[0].isLoopedPrevSegment(segment)
	) {
	return true;
	}
	return segment.reachable && segInfoMap[segment.id].calledInEveryPaths;
	}

	return {

	/**
	* Stacks a constructor information.
	* @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;
	const superClass = classNode.superClass;

	funcInfo = {
	upper: funcInfo,
	isConstructor: true,
	hasExtends: Boolean(superClass),
	superIsConstructor: isPossibleConstructor(superClass),
	codePath
	};
	} else {
	funcInfo = {
	upper: funcInfo,
	isConstructor: false,
	hasExtends: false,
	superIsConstructor: false,
	codePath
	};
	}
	},

	/**
	* Pops a constructor information.
	* And reports if `super()` lacked.
	* @param {CodePath} codePath - A code path which was ended.
	* @param {ASTNode} node - The current node.
	* @returns {void}
	*/
	onCodePathEnd(codePath, node) {
	const hasExtends = funcInfo.hasExtends;

	// Pop.
	funcInfo = funcInfo.upper;

	if (!hasExtends) {
	return;
	}

	// Reports if `super()` lacked.
	const segments = codePath.returnedSegments;
	const calledInEveryPaths = segments.every(isCalledInEveryPath);
	const calledInSomePaths = segments.some(isCalledInSomePath);

	if (!calledInEveryPaths) {
	context.report({
	messageId: calledInSomePaths
	? "missingSome"
	: "missingAll",
	node: node.parent
	});
	}
	},

	/**
	* Initialize information of a given code path segment.
	* @param {CodePathSegment} segment - A code path segment to initialize.
	* @returns {void}
	*/
	onCodePathSegmentStart(segment) {
	if (!(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends)) {
	return;
	}

	// Initialize info.
	const info = segInfoMap[segment.id] = {
	calledInSomePaths: false,
	calledInEveryPaths: false,
	validNodes: []
	};

	// When there are previous segments, aggregates these.
	const prevSegments = segment.prevSegments;

	if (prevSegments.length > 0) {
	info.calledInSomePaths = prevSegments.some(isCalledInSomePath);
	info.calledInEveryPaths = prevSegments.every(isCalledInEveryPath);
	}
	},

	/**
	* 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 (!(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends)) {
	return;
	}

	// Update information inside of the loop.
	const isRealLoop = toSegment.prevSegments.length >= 2;

	funcInfo.codePath.traverseSegments(
	{ first: toSegment, last: fromSegment },
	segment => {
	const info = segInfoMap[segment.id];
	const prevSegments = segment.prevSegments;

	// Updates flags.
	info.calledInSomePaths = prevSegments.some(isCalledInSomePath);
	info.calledInEveryPaths = prevSegments.every(isCalledInEveryPath);

	// If flags become true anew, reports the valid nodes.
	if (info.calledInSomePaths \|\| isRealLoop) {
	const nodes = info.validNodes;

	info.validNodes = [];

	for (let i = 0; i < nodes.length; ++i) {
	const node = nodes[i];

	context.report({
	messageId: "duplicate",
	node
	});
	}
	}
	}
	);
	},

	/**
	* Checks for a call of `super()`.
	* @param {ASTNode} node - A CallExpression node to check.
	* @returns {void}
	*/
	"CallExpression:exit"(node) {
	if (!(funcInfo && funcInfo.isConstructor)) {
	return;
	}

	// Skips except `super()`.
	if (node.callee.type !== "Super") {
	return;
	}

	// Reports if needed.
	if (funcInfo.hasExtends) {
	const segments = funcInfo.codePath.currentSegments;
	let duplicate = false;
	let info = null;

	for (let i = 0; i < segments.length; ++i) {
	const segment = segments[i];

	if (segment.reachable) {
	info = segInfoMap[segment.id];

	duplicate = duplicate \|\| info.calledInSomePaths;
	info.calledInSomePaths = info.calledInEveryPaths = true;
	}
	}

	if (info) {
	if (duplicate) {
	context.report({
	messageId: "duplicate",
	node
	});
	} else if (!funcInfo.superIsConstructor) {
	context.report({
	messageId: "badSuper",
	node
	});
	} else {
	info.validNodes.push(node);
	}
	}
	} else if (funcInfo.codePath.currentSegments.some(isReachable)) {
	context.report({
	messageId: "unexpected",
	node
	});
	}
	},

	/**
	* Set the mark to the returned path as `super()` was called.
	* @param {ASTNode} node - A ReturnStatement node to check.
	* @returns {void}
	*/
	ReturnStatement(node) {
	if (!(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends)) {
	return;
	}

	// Skips if no argument.
	if (!node.argument) {
	return;
	}

	// Returning argument is a substitute of 'super()'.
	const segments = funcInfo.codePath.currentSegments;

	for (let i = 0; i < segments.length; ++i) {
	const segment = segments[i];

	if (segment.reachable) {
	const info = segInfoMap[segment.id];

	info.calledInSomePaths = info.calledInEveryPaths = true;
	}
	}
	},

	/**
	* Resets state.
	* @returns {void}
	*/
	"Program:exit"() {
	segInfoMap = Object.create(null);
	}
	};
	}
	};