2025-04-19 23:12:19 -04:00

165 lines
4.2 KiB
JavaScript

/**
* @fileoverview Rule to enforce a particular function style
* @author Nicholas C. Zakas
*/
'use strict';
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../types').Rule.RuleModule} */
module.exports = {
meta: {
type: 'suggestion',
defaultOptions: [
'expression',
{
allowArrowFunctions: false,
overrides: {},
},
],
docs: {
description:
'Enforce the consistent use of either `function` declarations or expressions assigned to variables',
recommended: false,
frozen: true,
url: 'https://eslint.org/docs/latest/rules/func-style',
},
schema: [
{
enum: ['declaration', 'expression'],
},
{
type: 'object',
properties: {
allowArrowFunctions: {
type: 'boolean',
},
overrides: {
type: 'object',
properties: {
namedExports: {
enum: ['declaration', 'expression', 'ignore'],
},
},
additionalProperties: false,
},
},
additionalProperties: false,
},
],
messages: {
expression: 'Expected a function expression.',
declaration: 'Expected a function declaration.',
},
},
create(context) {
const [style, { allowArrowFunctions, overrides }] = context.options;
const enforceDeclarations = style === 'declaration';
const { namedExports: exportFunctionStyle } = overrides;
const stack = [];
const nodesToCheck = {
FunctionDeclaration(node) {
stack.push(false);
if (
!enforceDeclarations &&
node.parent.type !== 'ExportDefaultDeclaration' &&
(typeof exportFunctionStyle === 'undefined' ||
node.parent.type !== 'ExportNamedDeclaration')
) {
context.report({ node, messageId: 'expression' });
}
if (
node.parent.type === 'ExportNamedDeclaration' &&
exportFunctionStyle === 'expression'
) {
context.report({ node, messageId: 'expression' });
}
},
'FunctionDeclaration:exit'() {
stack.pop();
},
FunctionExpression(node) {
stack.push(false);
if (
enforceDeclarations &&
node.parent.type === 'VariableDeclarator' &&
(typeof exportFunctionStyle === 'undefined' ||
node.parent.parent.parent.type !== 'ExportNamedDeclaration')
) {
context.report({
node: node.parent,
messageId: 'declaration',
});
}
if (
node.parent.type === 'VariableDeclarator' &&
node.parent.parent.parent.type === 'ExportNamedDeclaration' &&
exportFunctionStyle === 'declaration'
) {
context.report({
node: node.parent,
messageId: 'declaration',
});
}
},
'FunctionExpression:exit'() {
stack.pop();
},
'ThisExpression, Super'() {
if (stack.length > 0) {
stack[stack.length - 1] = true;
}
},
};
if (!allowArrowFunctions) {
nodesToCheck.ArrowFunctionExpression = function () {
stack.push(false);
};
nodesToCheck['ArrowFunctionExpression:exit'] = function (node) {
const hasThisOrSuperExpr = stack.pop();
if (!hasThisOrSuperExpr && node.parent.type === 'VariableDeclarator') {
if (
enforceDeclarations &&
(typeof exportFunctionStyle === 'undefined' ||
node.parent.parent.parent.type !== 'ExportNamedDeclaration')
) {
context.report({
node: node.parent,
messageId: 'declaration',
});
}
if (
node.parent.parent.parent.type === 'ExportNamedDeclaration' &&
exportFunctionStyle === 'declaration'
) {
context.report({
node: node.parent,
messageId: 'declaration',
});
}
}
};
}
return nodesToCheck;
},
};