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/**
* @fileoverview A rule to set the maximum number of statements in a function.
* @author Ian Christian Myers
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
const { upperCaseFirst } = require("../shared/string-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "Enforce a maximum number of statements allowed in function blocks",
recommended: false,
url: "https://eslint.org/docs/latest/rules/max-statements"
},
schema: [
{
oneOf: [
{
type: "integer",
minimum: 0
},
{
type: "object",
properties: {
maximum: {
type: "integer",
minimum: 0
},
max: {
type: "integer",
minimum: 0
}
},
additionalProperties: false
}
]
},
{
type: "object",
properties: {
ignoreTopLevelFunctions: {
type: "boolean"
}
},
additionalProperties: false
}
],
messages: {
exceed: "{{name}} has too many statements ({{count}}). Maximum allowed is {{max}}."
}
},
create(context) {
//--------------------------------------------------------------------------
// Helpers
//--------------------------------------------------------------------------
const functionStack = [],
option = context.options[0],
ignoreTopLevelFunctions = context.options[1] && context.options[1].ignoreTopLevelFunctions || false,
topLevelFunctions = [];
let maxStatements = 10;
if (
typeof option === "object" &&
(Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max"))
) {
maxStatements = option.maximum || option.max;
} else if (typeof option === "number") {
maxStatements = option;
}
/**
* Reports a node if it has too many statements
* @param {ASTNode} node node to evaluate
* @param {int} count Number of statements in node
* @param {int} max Maximum number of statements allowed
* @returns {void}
* @private
*/
function reportIfTooManyStatements(node, count, max) {
if (count > max) {
const name = upperCaseFirst(astUtils.getFunctionNameWithKind(node));
context.report({
node,
messageId: "exceed",
data: { name, count, max }
});
}
}
/**
* When parsing a new function, store it in our function stack
* @returns {void}
* @private
*/
function startFunction() {
functionStack.push(0);
}
/**
* Evaluate the node at the end of function
* @param {ASTNode} node node to evaluate
* @returns {void}
* @private
*/
function endFunction(node) {
const count = functionStack.pop();
/*
* This rule does not apply to class static blocks, but we have to track them so
* that statements in them do not count as statements in the enclosing function.
*/
if (node.type === "StaticBlock") {
return;
}
if (ignoreTopLevelFunctions && functionStack.length === 0) {
topLevelFunctions.push({ node, count });
} else {
reportIfTooManyStatements(node, count, maxStatements);
}
}
/**
* Increment the count of the functions
* @param {ASTNode} node node to evaluate
* @returns {void}
* @private
*/
function countStatements(node) {
functionStack[functionStack.length - 1] += node.body.length;
}
//--------------------------------------------------------------------------
// Public API
//--------------------------------------------------------------------------
return {
FunctionDeclaration: startFunction,
FunctionExpression: startFunction,
ArrowFunctionExpression: startFunction,
StaticBlock: startFunction,
BlockStatement: countStatements,
"FunctionDeclaration:exit": endFunction,
"FunctionExpression:exit": endFunction,
"ArrowFunctionExpression:exit": endFunction,
"StaticBlock:exit": endFunction,
"Program:exit"() {
if (topLevelFunctions.length === 1) {
return;
}
topLevelFunctions.forEach(element => {
const count = element.count;
const node = element.node;
reportIfTooManyStatements(node, count, maxStatements);
});
}
};
}
};