217 lines
5.7 KiB
Plaintext
217 lines
5.7 KiB
Plaintext
/**
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* @fileoverview Enforce return after a callback.
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* @author Jamund Ferguson
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* @deprecated in ESLint v7.0.0
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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meta: {
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deprecated: {
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message: "Node.js rules were moved out of ESLint core.",
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url: "https://eslint.org/docs/latest/use/migrating-to-7.0.0#deprecate-node-rules",
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deprecatedSince: "7.0.0",
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availableUntil: null,
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replacedBy: [
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{
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message:
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"eslint-plugin-n now maintains deprecated Node.js-related rules.",
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plugin: {
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name: "eslint-plugin-n",
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url: "https://github.com/eslint-community/eslint-plugin-n",
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},
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rule: {
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name: "callback-return",
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url: "https://github.com/eslint-community/eslint-plugin-n/tree/master/docs/rules/callback-return.md",
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},
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},
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],
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},
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type: "suggestion",
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docs: {
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description: "Require `return` statements after callbacks",
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recommended: false,
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url: "https://eslint.org/docs/latest/rules/callback-return",
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},
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schema: [
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{
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type: "array",
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items: { type: "string" },
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},
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],
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messages: {
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missingReturn: "Expected return with your callback function.",
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},
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},
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create(context) {
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const callbacks = context.options[0] || ["callback", "cb", "next"],
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sourceCode = context.sourceCode;
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//--------------------------------------------------------------------------
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// Helpers
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//--------------------------------------------------------------------------
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/**
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* Find the closest parent matching a list of types.
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* @param {ASTNode} node The node whose parents we are searching
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* @param {Array} types The node types to match
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* @returns {ASTNode} The matched node or undefined.
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*/
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function findClosestParentOfType(node, types) {
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if (!node.parent) {
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return null;
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}
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if (!types.includes(node.parent.type)) {
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return findClosestParentOfType(node.parent, types);
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}
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return node.parent;
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}
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/**
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* Check to see if a node contains only identifiers
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* @param {ASTNode} node The node to check
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* @returns {boolean} Whether or not the node contains only identifiers
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*/
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function containsOnlyIdentifiers(node) {
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if (node.type === "Identifier") {
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return true;
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}
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if (node.type === "MemberExpression") {
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if (node.object.type === "Identifier") {
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return true;
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}
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if (node.object.type === "MemberExpression") {
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return containsOnlyIdentifiers(node.object);
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}
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}
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return false;
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}
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/**
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* Check to see if a CallExpression is in our callback list.
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* @param {ASTNode} node The node to check against our callback names list.
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* @returns {boolean} Whether or not this function matches our callback name.
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*/
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function isCallback(node) {
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return (
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containsOnlyIdentifiers(node.callee) &&
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callbacks.includes(sourceCode.getText(node.callee))
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);
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}
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/**
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* Determines whether or not the callback is part of a callback expression.
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* @param {ASTNode} node The callback node
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* @param {ASTNode} parentNode The expression node
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* @returns {boolean} Whether or not this is part of a callback expression
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*/
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function isCallbackExpression(node, parentNode) {
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// ensure the parent node exists and is an expression
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if (!parentNode || parentNode.type !== "ExpressionStatement") {
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return false;
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}
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// cb()
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if (parentNode.expression === node) {
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return true;
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}
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// special case for cb && cb() and similar
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if (
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parentNode.expression.type === "BinaryExpression" ||
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parentNode.expression.type === "LogicalExpression"
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) {
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if (parentNode.expression.right === node) {
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return true;
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}
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}
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return false;
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}
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//--------------------------------------------------------------------------
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// Public
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//--------------------------------------------------------------------------
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return {
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CallExpression(node) {
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// if we're not a callback we can return
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if (!isCallback(node)) {
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return;
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}
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// find the closest block, return or loop
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const closestBlock =
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findClosestParentOfType(node, [
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"BlockStatement",
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"ReturnStatement",
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"ArrowFunctionExpression",
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]) || {};
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// if our parent is a return we know we're ok
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if (closestBlock.type === "ReturnStatement") {
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return;
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}
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// arrow functions don't always have blocks and implicitly return
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if (closestBlock.type === "ArrowFunctionExpression") {
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return;
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}
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// block statements are part of functions and most if statements
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if (closestBlock.type === "BlockStatement") {
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// find the last item in the block
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const lastItem = closestBlock.body.at(-1);
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// if the callback is the last thing in a block that might be ok
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if (isCallbackExpression(node, lastItem)) {
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const parentType = closestBlock.parent.type;
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// but only if the block is part of a function
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if (
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parentType === "FunctionExpression" ||
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parentType === "FunctionDeclaration" ||
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parentType === "ArrowFunctionExpression"
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) {
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return;
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}
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}
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// ending a block with a return is also ok
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if (lastItem.type === "ReturnStatement") {
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// but only if the callback is immediately before
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if (
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isCallbackExpression(node, closestBlock.body.at(-2))
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) {
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return;
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}
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}
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}
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// as long as you're the child of a function at this point you should be asked to return
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if (
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findClosestParentOfType(node, [
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"FunctionDeclaration",
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"FunctionExpression",
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"ArrowFunctionExpression",
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])
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) {
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context.report({ node, messageId: "missingReturn" });
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}
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},
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};
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},
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};
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