@typescript-eslint/eslint-plugin
Version:
TypeScript plugin for ESLint
201 lines (200 loc) • 9 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
const scope_manager_1 = require("@typescript-eslint/scope-manager");
const utils_1 = require("@typescript-eslint/utils");
const util_1 = require("../util");
exports.default = (0, util_1.createRule)({
name: 'no-redeclare',
meta: {
type: 'suggestion',
docs: {
description: 'Disallow variable redeclaration',
extendsBaseRule: true,
},
messages: {
redeclared: "'{{id}}' is already defined.",
redeclaredAsBuiltin: "'{{id}}' is already defined as a built-in global variable.",
redeclaredBySyntax: "'{{id}}' is already defined by a variable declaration.",
},
schema: [
{
type: 'object',
additionalProperties: false,
properties: {
builtinGlobals: {
type: 'boolean',
description: 'Whether to report shadowing of built-in global variables.',
},
ignoreDeclarationMerge: {
type: 'boolean',
description: 'Whether to ignore declaration merges between certain TypeScript declaration types.',
},
},
},
],
},
defaultOptions: [
{
builtinGlobals: true,
ignoreDeclarationMerge: true,
},
],
create(context, [options]) {
const CLASS_DECLARATION_MERGE_NODES = new Set([
utils_1.AST_NODE_TYPES.ClassDeclaration,
utils_1.AST_NODE_TYPES.TSInterfaceDeclaration,
utils_1.AST_NODE_TYPES.TSModuleDeclaration,
]);
const FUNCTION_DECLARATION_MERGE_NODES = new Set([
utils_1.AST_NODE_TYPES.FunctionDeclaration,
utils_1.AST_NODE_TYPES.TSModuleDeclaration,
]);
const ENUM_DECLARATION_MERGE_NODES = new Set([
utils_1.AST_NODE_TYPES.TSEnumDeclaration,
utils_1.AST_NODE_TYPES.TSModuleDeclaration,
]);
function* iterateDeclarations(variable) {
if (options.builtinGlobals &&
'eslintImplicitGlobalSetting' in variable &&
(variable.eslintImplicitGlobalSetting === 'readonly' ||
variable.eslintImplicitGlobalSetting === 'writable')) {
yield { type: 'builtin' };
}
if ('eslintExplicitGlobalComments' in variable &&
variable.eslintExplicitGlobalComments) {
for (const comment of variable.eslintExplicitGlobalComments) {
yield {
loc: (0, util_1.getNameLocationInGlobalDirectiveComment)(context.sourceCode, comment, variable.name),
node: comment,
type: 'comment',
};
}
}
const identifiers = variable.identifiers
.map(id => ({
identifier: id,
parent: id.parent,
}))
// ignore function declarations because TS will treat them as an overload
.filter(({ parent }) => parent.type !== utils_1.AST_NODE_TYPES.TSDeclareFunction);
if (options.ignoreDeclarationMerge && identifiers.length > 1) {
if (
// interfaces merging
identifiers.every(({ parent }) => parent.type === utils_1.AST_NODE_TYPES.TSInterfaceDeclaration)) {
return;
}
if (
// namespace/module merging
identifiers.every(({ parent }) => parent.type === utils_1.AST_NODE_TYPES.TSModuleDeclaration)) {
return;
}
if (
// class + interface/namespace merging
identifiers.every(({ parent }) => CLASS_DECLARATION_MERGE_NODES.has(parent.type))) {
const classDecls = identifiers.filter(({ parent }) => parent.type === utils_1.AST_NODE_TYPES.ClassDeclaration);
if (classDecls.length === 1) {
// safe declaration merging
return;
}
// there's more than one class declaration, which needs to be reported
for (const { identifier } of classDecls) {
yield { loc: identifier.loc, node: identifier, type: 'syntax' };
}
return;
}
if (
// class + interface/namespace merging
identifiers.every(({ parent }) => FUNCTION_DECLARATION_MERGE_NODES.has(parent.type))) {
const functionDecls = identifiers.filter(({ parent }) => parent.type === utils_1.AST_NODE_TYPES.FunctionDeclaration);
if (functionDecls.length === 1) {
// safe declaration merging
return;
}
// there's more than one function declaration, which needs to be reported
for (const { identifier } of functionDecls) {
yield { loc: identifier.loc, node: identifier, type: 'syntax' };
}
return;
}
if (
// enum + namespace merging
identifiers.every(({ parent }) => ENUM_DECLARATION_MERGE_NODES.has(parent.type))) {
const enumDecls = identifiers.filter(({ parent }) => parent.type === utils_1.AST_NODE_TYPES.TSEnumDeclaration);
if (enumDecls.length === 1) {
// safe declaration merging
return;
}
// there's more than one enum declaration, which needs to be reported
for (const { identifier } of enumDecls) {
yield { loc: identifier.loc, node: identifier, type: 'syntax' };
}
return;
}
}
for (const { identifier } of identifiers) {
yield { loc: identifier.loc, node: identifier, type: 'syntax' };
}
}
function findVariablesInScope(scope) {
for (const variable of scope.variables) {
const [declaration, ...extraDeclarations] = iterateDeclarations(variable);
if (extraDeclarations.length === 0) {
continue;
}
/*
* If the type of a declaration is different from the type of
* the first declaration, it shows the location of the first
* declaration.
*/
const detailMessageId = declaration.type === 'builtin'
? 'redeclaredAsBuiltin'
: 'redeclaredBySyntax';
const data = { id: variable.name };
// Report extra declarations.
for (const { loc, node, type } of extraDeclarations) {
const messageId = type === declaration.type ? 'redeclared' : detailMessageId;
if (node) {
context.report({ loc, node, messageId, data });
}
else if (loc) {
context.report({ loc, messageId, data });
}
}
}
}
/**
* Find variables in the current scope.
*/
function checkForBlock(node) {
const scope = context.sourceCode.getScope(node);
/*
* In ES5, some node type such as `BlockStatement` doesn't have that scope.
* `scope.block` is a different node in such a case.
*/
if (scope.block === node) {
findVariablesInScope(scope);
}
}
return {
ArrowFunctionExpression: checkForBlock,
BlockStatement: checkForBlock,
ForInStatement: checkForBlock,
ForOfStatement: checkForBlock,
ForStatement: checkForBlock,
FunctionDeclaration: checkForBlock,
FunctionExpression: checkForBlock,
Program(node) {
const scope = context.sourceCode.getScope(node);
findVariablesInScope(scope);
// Node.js or ES modules has a special scope.
if (scope.type === scope_manager_1.ScopeType.global &&
scope.childScopes[0] &&
// The special scope's block is the Program node.
scope.block === scope.childScopes[0].block) {
findVariablesInScope(scope.childScopes[0]);
}
},
SwitchStatement: checkForBlock,
};
},
});