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