node/tools/eslint-rules/no-duplicate-requires.js

69 lines
1.7 KiB
JavaScript
Raw Normal View History

/**
* @fileoverview Ensure modules are not required twice at top level of a module
* @author devsnek
*/
'use strict';
const { isRequireCall } = require('./rules-utils.js');
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
function isString(node) {
return node && node.type === 'Literal' && typeof node.value === 'string';
}
function isTopLevel(node) {
do {
if (node.type === 'FunctionDeclaration' ||
node.type === 'FunctionExpression' ||
node.type === 'ArrowFunctionExpression' ||
node.type === 'ClassBody' ||
node.type === 'MethodDefinition') {
return false;
}
} while (node = node.parent);
return true;
}
module.exports = (context) => {
if (context.parserOptions.sourceType === 'module') {
return {};
}
function getRequiredModuleNameFromCall(node) {
// Node has arguments and first argument is string
if (node.arguments.length && isString(node.arguments[0])) {
return node.arguments[0].value.trim();
}
return undefined;
}
const required = new Set();
const rules = {
CallExpression: (node) => {
if (isRequireCall(node) && isTopLevel(node)) {
const moduleName = getRequiredModuleNameFromCall(node);
if (moduleName === undefined) {
return;
}
if (required.has(moduleName)) {
context.report(
node,
'\'{{moduleName}}\' require is duplicated.',
{ moduleName }
);
} else {
required.add(moduleName);
}
}
},
};
return rules;
};