+++ /dev/null
-/**
- * @fileoverview Enforce return after a callback.
- * @author Jamund Ferguson
- */
-"use strict";
-
-//------------------------------------------------------------------------------
-// Rule Definition
-//------------------------------------------------------------------------------
-
-module.exports = {
- meta: {
- type: "suggestion",
-
- docs: {
- description: "require `return` statements after callbacks",
- category: "Node.js and CommonJS",
- recommended: false,
- url: "https://eslint.org/docs/rules/callback-return"
- },
-
- schema: [{
- type: "array",
- items: { type: "string" }
- }],
-
- messages: {
- missingReturn: "Expected return with your callback function."
- }
- },
-
- create(context) {
-
- const callbacks = context.options[0] || ["callback", "cb", "next"],
- sourceCode = context.getSourceCode();
-
- //--------------------------------------------------------------------------
- // Helpers
- //--------------------------------------------------------------------------
-
- /**
- * Find the closest parent matching a list of types.
- * @param {ASTNode} node The node whose parents we are searching
- * @param {Array} types The node types to match
- * @returns {ASTNode} The matched node or undefined.
- */
- function findClosestParentOfType(node, types) {
- if (!node.parent) {
- return null;
- }
- if (types.indexOf(node.parent.type) === -1) {
- return findClosestParentOfType(node.parent, types);
- }
- return node.parent;
- }
-
- /**
- * Check to see if a node contains only identifers
- * @param {ASTNode} node The node to check
- * @returns {boolean} Whether or not the node contains only identifers
- */
- function containsOnlyIdentifiers(node) {
- if (node.type === "Identifier") {
- return true;
- }
-
- if (node.type === "MemberExpression") {
- if (node.object.type === "Identifier") {
- return true;
- }
- if (node.object.type === "MemberExpression") {
- return containsOnlyIdentifiers(node.object);
- }
- }
-
- return false;
- }
-
- /**
- * Check to see if a CallExpression is in our callback list.
- * @param {ASTNode} node The node to check against our callback names list.
- * @returns {boolean} Whether or not this function matches our callback name.
- */
- function isCallback(node) {
- return containsOnlyIdentifiers(node.callee) && callbacks.indexOf(sourceCode.getText(node.callee)) > -1;
- }
-
- /**
- * Determines whether or not the callback is part of a callback expression.
- * @param {ASTNode} node The callback node
- * @param {ASTNode} parentNode The expression node
- * @returns {boolean} Whether or not this is part of a callback expression
- */
- function isCallbackExpression(node, parentNode) {
-
- // ensure the parent node exists and is an expression
- if (!parentNode || parentNode.type !== "ExpressionStatement") {
- return false;
- }
-
- // cb()
- if (parentNode.expression === node) {
- return true;
- }
-
- // special case for cb && cb() and similar
- if (parentNode.expression.type === "BinaryExpression" || parentNode.expression.type === "LogicalExpression") {
- if (parentNode.expression.right === node) {
- return true;
- }
- }
-
- return false;
- }
-
- //--------------------------------------------------------------------------
- // Public
- //--------------------------------------------------------------------------
-
- return {
- CallExpression(node) {
-
- // if we're not a callback we can return
- if (!isCallback(node)) {
- return;
- }
-
- // find the closest block, return or loop
- const closestBlock = findClosestParentOfType(node, ["BlockStatement", "ReturnStatement", "ArrowFunctionExpression"]) || {};
-
- // if our parent is a return we know we're ok
- if (closestBlock.type === "ReturnStatement") {
- return;
- }
-
- // arrow functions don't always have blocks and implicitly return
- if (closestBlock.type === "ArrowFunctionExpression") {
- return;
- }
-
- // block statements are part of functions and most if statements
- if (closestBlock.type === "BlockStatement") {
-
- // find the last item in the block
- const lastItem = closestBlock.body[closestBlock.body.length - 1];
-
- // if the callback is the last thing in a block that might be ok
- if (isCallbackExpression(node, lastItem)) {
-
- const parentType = closestBlock.parent.type;
-
- // but only if the block is part of a function
- if (parentType === "FunctionExpression" ||
- parentType === "FunctionDeclaration" ||
- parentType === "ArrowFunctionExpression"
- ) {
- return;
- }
-
- }
-
- // ending a block with a return is also ok
- if (lastItem.type === "ReturnStatement") {
-
- // but only if the callback is immediately before
- if (isCallbackExpression(node, closestBlock.body[closestBlock.body.length - 2])) {
- return;
- }
- }
-
- }
-
- // as long as you're the child of a function at this point you should be asked to return
- if (findClosestParentOfType(node, ["FunctionDeclaration", "FunctionExpression", "ArrowFunctionExpression"])) {
- context.report({ node, messageId: "missingReturn" });
- }
-
- }
-
- };
- }
-};
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