| /** |
| * @fileoverview Rule to enforce a maximum number of nested callbacks. |
| * @author Ian Christian Myers |
| */ |
| |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "suggestion", |
| |
| docs: { |
| description: "enforce a maximum depth that callbacks can be nested", |
| category: "Stylistic Issues", |
| recommended: false, |
| url: "https://eslint.org/docs/rules/max-nested-callbacks" |
| }, |
| |
| schema: [ |
| { |
| oneOf: [ |
| { |
| type: "integer", |
| minimum: 0 |
| }, |
| { |
| type: "object", |
| properties: { |
| maximum: { |
| type: "integer", |
| minimum: 0 |
| }, |
| max: { |
| type: "integer", |
| minimum: 0 |
| } |
| }, |
| additionalProperties: false |
| } |
| ] |
| } |
| ], |
| messages: { |
| exceed: "Too many nested callbacks ({{num}}). Maximum allowed is {{max}}." |
| } |
| }, |
| |
| create(context) { |
| |
| //-------------------------------------------------------------------------- |
| // Constants |
| //-------------------------------------------------------------------------- |
| const option = context.options[0]; |
| let THRESHOLD = 10; |
| |
| if ( |
| typeof option === "object" && |
| (Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max")) |
| ) { |
| THRESHOLD = option.maximum || option.max; |
| } else if (typeof option === "number") { |
| THRESHOLD = option; |
| } |
| |
| //-------------------------------------------------------------------------- |
| // Helpers |
| //-------------------------------------------------------------------------- |
| |
| const callbackStack = []; |
| |
| /** |
| * Checks a given function node for too many callbacks. |
| * @param {ASTNode} node The node to check. |
| * @returns {void} |
| * @private |
| */ |
| function checkFunction(node) { |
| const parent = node.parent; |
| |
| if (parent.type === "CallExpression") { |
| callbackStack.push(node); |
| } |
| |
| if (callbackStack.length > THRESHOLD) { |
| const opts = { num: callbackStack.length, max: THRESHOLD }; |
| |
| context.report({ node, messageId: "exceed", data: opts }); |
| } |
| } |
| |
| /** |
| * Pops the call stack. |
| * @returns {void} |
| * @private |
| */ |
| function popStack() { |
| callbackStack.pop(); |
| } |
| |
| //-------------------------------------------------------------------------- |
| // Public API |
| //-------------------------------------------------------------------------- |
| |
| return { |
| ArrowFunctionExpression: checkFunction, |
| "ArrowFunctionExpression:exit": popStack, |
| |
| FunctionExpression: checkFunction, |
| "FunctionExpression:exit": popStack |
| }; |
| |
| } |
| }; |