no-unused-vars.js
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"use strict";
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
__setModuleDefault(result, mod);
return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
const experimental_utils_1 = require("@typescript-eslint/experimental-utils");
const scope_manager_1 = require("@typescript-eslint/scope-manager");
const ast_utils_1 = require("eslint/lib/rules/utils/ast-utils");
const util = __importStar(require("../util"));
exports.default = util.createRule({
name: 'no-unused-vars',
meta: {
type: 'problem',
docs: {
description: 'Disallow unused variables',
category: 'Variables',
recommended: 'warn',
extendsBaseRule: true,
},
schema: [
{
oneOf: [
{
enum: ['all', 'local'],
},
{
type: 'object',
properties: {
vars: {
enum: ['all', 'local'],
},
varsIgnorePattern: {
type: 'string',
},
args: {
enum: ['all', 'after-used', 'none'],
},
ignoreRestSiblings: {
type: 'boolean',
},
argsIgnorePattern: {
type: 'string',
},
caughtErrors: {
enum: ['all', 'none'],
},
caughtErrorsIgnorePattern: {
type: 'string',
},
},
additionalProperties: false,
},
],
},
],
messages: {
unusedVar: "'{{varName}}' is {{action}} but never used{{additional}}.",
},
},
defaultOptions: [{}],
create(context) {
const filename = context.getFilename();
const sourceCode = context.getSourceCode();
const MODULE_DECL_CACHE = new Map();
const options = (() => {
var _a, _b, _c, _d;
const options = {
vars: 'all',
args: 'after-used',
ignoreRestSiblings: false,
caughtErrors: 'none',
};
const firstOption = context.options[0];
if (firstOption) {
if (typeof firstOption === 'string') {
options.vars = firstOption;
}
else {
options.vars = (_a = firstOption.vars) !== null && _a !== void 0 ? _a : options.vars;
options.args = (_b = firstOption.args) !== null && _b !== void 0 ? _b : options.args;
options.ignoreRestSiblings = (_c = firstOption.ignoreRestSiblings) !== null && _c !== void 0 ? _c : options.ignoreRestSiblings;
options.caughtErrors = (_d = firstOption.caughtErrors) !== null && _d !== void 0 ? _d : options.caughtErrors;
if (firstOption.varsIgnorePattern) {
options.varsIgnorePattern = new RegExp(firstOption.varsIgnorePattern, 'u');
}
if (firstOption.argsIgnorePattern) {
options.argsIgnorePattern = new RegExp(firstOption.argsIgnorePattern, 'u');
}
if (firstOption.caughtErrorsIgnorePattern) {
options.caughtErrorsIgnorePattern = new RegExp(firstOption.caughtErrorsIgnorePattern, 'u');
}
}
}
return options;
})();
function collectUnusedVariables() {
var _a, _b, _c;
/**
* Determines if a variable has a sibling rest property
* @param variable eslint-scope variable object.
* @returns True if the variable is exported, false if not.
*/
function hasRestSpreadSibling(variable) {
if (options.ignoreRestSiblings) {
return variable.defs.some(def => {
const propertyNode = def.name.parent;
const patternNode = propertyNode.parent;
return (propertyNode.type === experimental_utils_1.AST_NODE_TYPES.Property &&
patternNode.type === experimental_utils_1.AST_NODE_TYPES.ObjectPattern &&
patternNode.properties[patternNode.properties.length - 1].type ===
experimental_utils_1.AST_NODE_TYPES.RestElement);
});
}
return false;
}
/**
* Checks whether the given variable is after the last used parameter.
* @param variable The variable to check.
* @returns `true` if the variable is defined after the last used parameter.
*/
function isAfterLastUsedArg(variable) {
const def = variable.defs[0];
const params = context.getDeclaredVariables(def.node);
const posteriorParams = params.slice(params.indexOf(variable) + 1);
// If any used parameters occur after this parameter, do not report.
return !posteriorParams.some(v => v.references.length > 0 || v.eslintUsed);
}
const unusedVariablesOriginal = util.collectUnusedVariables(context);
const unusedVariablesReturn = [];
for (const variable of unusedVariablesOriginal) {
// explicit global variables don't have definitions.
if (variable.defs.length === 0) {
unusedVariablesReturn.push(variable);
continue;
}
const def = variable.defs[0];
if (variable.scope.type === experimental_utils_1.TSESLint.Scope.ScopeType.global &&
options.vars === 'local') {
// skip variables in the global scope if configured to
continue;
}
// skip catch variables
if (def.type === experimental_utils_1.TSESLint.Scope.DefinitionType.CatchClause) {
if (options.caughtErrors === 'none') {
continue;
}
// skip ignored parameters
if ('name' in def.name && ((_a = options.caughtErrorsIgnorePattern) === null || _a === void 0 ? void 0 : _a.test(def.name.name))) {
continue;
}
}
if (def.type === experimental_utils_1.TSESLint.Scope.DefinitionType.Parameter) {
// if "args" option is "none", skip any parameter
if (options.args === 'none') {
continue;
}
// skip ignored parameters
if ('name' in def.name && ((_b = options.argsIgnorePattern) === null || _b === void 0 ? void 0 : _b.test(def.name.name))) {
continue;
}
// if "args" option is "after-used", skip used variables
if (options.args === 'after-used' &&
util.isFunction(def.name.parent) &&
!isAfterLastUsedArg(variable)) {
continue;
}
}
else {
// skip ignored variables
if ('name' in def.name && ((_c = options.varsIgnorePattern) === null || _c === void 0 ? void 0 : _c.test(def.name.name))) {
continue;
}
}
if (hasRestSpreadSibling(variable)) {
continue;
}
// in case another rule has run and used the collectUnusedVariables,
// we want to ensure our selectors that marked variables as used are respected
if (variable.eslintUsed) {
continue;
}
unusedVariablesReturn.push(variable);
}
return unusedVariablesReturn;
}
return {
// declaration file handling
[ambientDeclarationSelector(experimental_utils_1.AST_NODE_TYPES.Program, true)](node) {
if (!util.isDefinitionFile(filename)) {
return;
}
markDeclarationChildAsUsed(node);
},
// children of a namespace that is a child of a declared namespace are auto-exported
[ambientDeclarationSelector('TSModuleDeclaration[declare = true] > TSModuleBlock TSModuleDeclaration > TSModuleBlock', false)](node) {
markDeclarationChildAsUsed(node);
},
// declared namespace handling
[ambientDeclarationSelector('TSModuleDeclaration[declare = true] > TSModuleBlock', false)](node) {
var _a;
const moduleDecl = util.nullThrows((_a = node.parent) === null || _a === void 0 ? void 0 : _a.parent, util.NullThrowsReasons.MissingParent);
// declared ambient modules with an `export =` statement will only export that one thing
// all other statements are not automatically exported in this case
if (moduleDecl.id.type === experimental_utils_1.AST_NODE_TYPES.Literal &&
checkModuleDeclForExportEquals(moduleDecl)) {
return;
}
markDeclarationChildAsUsed(node);
},
// collect
'Program:exit'(programNode) {
/**
* Generates the message data about the variable being defined and unused,
* including the ignore pattern if configured.
* @param unusedVar eslint-scope variable object.
* @returns The message data to be used with this unused variable.
*/
function getDefinedMessageData(unusedVar) {
var _a;
const defType = (_a = unusedVar === null || unusedVar === void 0 ? void 0 : unusedVar.defs[0]) === null || _a === void 0 ? void 0 : _a.type;
let type;
let pattern;
if (defType === experimental_utils_1.TSESLint.Scope.DefinitionType.CatchClause &&
options.caughtErrorsIgnorePattern) {
type = 'args';
pattern = options.caughtErrorsIgnorePattern.toString();
}
else if (defType === experimental_utils_1.TSESLint.Scope.DefinitionType.Parameter &&
options.argsIgnorePattern) {
type = 'args';
pattern = options.argsIgnorePattern.toString();
}
else if (defType !== experimental_utils_1.TSESLint.Scope.DefinitionType.Parameter &&
options.varsIgnorePattern) {
type = 'vars';
pattern = options.varsIgnorePattern.toString();
}
const additional = type
? `. Allowed unused ${type} must match ${pattern}`
: '';
return {
varName: unusedVar.name,
action: 'defined',
additional,
};
}
/**
* Generate the warning message about the variable being
* assigned and unused, including the ignore pattern if configured.
* @param unusedVar eslint-scope variable object.
* @returns The message data to be used with this unused variable.
*/
function getAssignedMessageData(unusedVar) {
const additional = options.varsIgnorePattern
? `. Allowed unused vars must match ${options.varsIgnorePattern.toString()}`
: '';
return {
varName: unusedVar.name,
action: 'assigned a value',
additional,
};
}
const unusedVars = collectUnusedVariables();
for (let i = 0, l = unusedVars.length; i < l; ++i) {
const unusedVar = unusedVars[i];
// Report the first declaration.
if (unusedVar.defs.length > 0) {
context.report({
node: unusedVar.references.length
? unusedVar.references[unusedVar.references.length - 1]
.identifier
: unusedVar.identifiers[0],
messageId: 'unusedVar',
data: unusedVar.references.some(ref => ref.isWrite())
? getAssignedMessageData(unusedVar)
: getDefinedMessageData(unusedVar),
});
// If there are no regular declaration, report the first `/*globals*/` comment directive.
}
else if ('eslintExplicitGlobalComments' in unusedVar &&
unusedVar.eslintExplicitGlobalComments) {
const directiveComment = unusedVar.eslintExplicitGlobalComments[0];
context.report({
node: programNode,
loc: ast_utils_1.getNameLocationInGlobalDirectiveComment(sourceCode, directiveComment, unusedVar.name),
messageId: 'unusedVar',
data: getDefinedMessageData(unusedVar),
});
}
}
},
};
function checkModuleDeclForExportEquals(node) {
var _a, _b;
const cached = MODULE_DECL_CACHE.get(node);
if (cached != null) {
return cached;
}
for (const statement of (_b = (_a = node.body) === null || _a === void 0 ? void 0 : _a.body) !== null && _b !== void 0 ? _b : []) {
if (statement.type === experimental_utils_1.AST_NODE_TYPES.TSExportAssignment) {
MODULE_DECL_CACHE.set(node, true);
return true;
}
}
MODULE_DECL_CACHE.set(node, false);
return false;
}
function ambientDeclarationSelector(parent, childDeclare) {
return [
// Types are ambiently exported
`${parent} > :matches(${[
experimental_utils_1.AST_NODE_TYPES.TSInterfaceDeclaration,
experimental_utils_1.AST_NODE_TYPES.TSTypeAliasDeclaration,
].join(', ')})`,
// Value things are ambiently exported if they are "declare"d
`${parent} > :matches(${[
experimental_utils_1.AST_NODE_TYPES.ClassDeclaration,
experimental_utils_1.AST_NODE_TYPES.TSDeclareFunction,
experimental_utils_1.AST_NODE_TYPES.TSEnumDeclaration,
experimental_utils_1.AST_NODE_TYPES.TSModuleDeclaration,
experimental_utils_1.AST_NODE_TYPES.VariableDeclaration,
].join(', ')})${childDeclare ? '[declare = true]' : ''}`,
].join(', ');
}
function markDeclarationChildAsUsed(node) {
var _a;
const identifiers = [];
switch (node.type) {
case experimental_utils_1.AST_NODE_TYPES.TSInterfaceDeclaration:
case experimental_utils_1.AST_NODE_TYPES.TSTypeAliasDeclaration:
case experimental_utils_1.AST_NODE_TYPES.ClassDeclaration:
case experimental_utils_1.AST_NODE_TYPES.FunctionDeclaration:
case experimental_utils_1.AST_NODE_TYPES.TSDeclareFunction:
case experimental_utils_1.AST_NODE_TYPES.TSEnumDeclaration:
case experimental_utils_1.AST_NODE_TYPES.TSModuleDeclaration:
if (((_a = node.id) === null || _a === void 0 ? void 0 : _a.type) === experimental_utils_1.AST_NODE_TYPES.Identifier) {
identifiers.push(node.id);
}
break;
case experimental_utils_1.AST_NODE_TYPES.VariableDeclaration:
for (const declaration of node.declarations) {
visitPattern(declaration, pattern => {
identifiers.push(pattern);
});
}
break;
}
let scope = context.getScope();
const shouldUseUpperScope = [
experimental_utils_1.AST_NODE_TYPES.TSModuleDeclaration,
experimental_utils_1.AST_NODE_TYPES.TSDeclareFunction,
].includes(node.type);
if (scope.variableScope !== scope) {
scope = scope.variableScope;
}
else if (shouldUseUpperScope && scope.upper) {
scope = scope.upper;
}
for (const id of identifiers) {
const superVar = scope.set.get(id.name);
if (superVar) {
superVar.eslintUsed = true;
}
}
}
function visitPattern(node, cb) {
const visitor = new scope_manager_1.PatternVisitor({}, node, cb);
visitor.visit(node);
}
},
});
/*
###### TODO ######
Edge cases that aren't currently handled due to laziness and them being super edgy edge cases
--- function params referenced in typeof type refs in the function declaration ---
--- NOTE - TS gets these cases wrong
function _foo(
arg: number // arg should be unused
): typeof arg {
return 1 as any;
}
function _bar(
arg: number, // arg should be unused
_arg2: typeof arg,
) {}
--- function names referenced in typeof type refs in the function declaration ---
--- NOTE - TS gets these cases right
function foo( // foo should be unused
): typeof foo {
return 1 as any;
}
function bar( // bar should be unused
_arg: typeof bar
) {}
--- if an interface is merged into a namespace ---
--- NOTE - TS gets these cases wrong
namespace Test {
interface Foo { // Foo should be unused here
a: string;
}
export namespace Foo {
export type T = 'b';
}
}
type T = Test.Foo; // Error: Namespace 'Test' has no exported member 'Foo'.
namespace Test {
export interface Foo {
a: string;
}
namespace Foo { // Foo should be unused here
export type T = 'b';
}
}
type T = Test.Foo.T; // Error: Namespace 'Test' has no exported member 'Foo'.
*/
/*
###### TODO ######
We currently extend base `no-unused-vars` implementation because it's easier and lighter-weight.
Because of this, there are a few false-negatives which won't get caught.
We could fix these if we fork the base rule; but that's a lot of code (~650 lines) to add in.
I didn't want to do that just yet without some real-world issues, considering these are pretty rare edge-cases.
These cases are mishandled because the base rule assumes that each variable has one def, but type-value shadowing
creates a variable with two defs
--- type-only or value-only references to type/value shadowed variables ---
--- NOTE - TS gets these cases wrong
type T = 1;
const T = 2; // this T should be unused
type U = T; // this U should be unused
const U = 3;
const _V = U;
--- partially exported type/value shadowed variables ---
--- NOTE - TS gets these cases wrong
export interface Foo {}
const Foo = 1; // this Foo should be unused
interface Bar {} // this Bar should be unused
export const Bar = 1;
*/
//# sourceMappingURL=no-unused-vars.js.map