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no-unused-vars.js
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no-unused-vars.js
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/**
* @fileoverview Tests for no-unused-vars rule.
* @author Ilya Volodin
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const rule = require("../../../lib/rules/no-unused-vars"),
RuleTester = require("../../../lib/rule-tester/rule-tester");
//------------------------------------------------------------------------------
// Tests
//------------------------------------------------------------------------------
const ruleTester = new RuleTester({
languageOptions: {
ecmaVersion: 5,
sourceType: "script"
},
plugins: {
custom: {
rules: {
"use-every-a": {
create(context) {
const sourceCode = context.sourceCode;
/**
* Mark a variable as used
* @param {ASTNode} node The node representing the scope to search
* @returns {void}
* @private
*/
function useA(node) {
sourceCode.markVariableAsUsed("a", node);
}
return {
VariableDeclaration: useA,
ReturnStatement: useA
};
}
}
}
}
}
});
/**
* Returns an expected error for defined-but-not-used variables.
* @param {string} varName The name of the variable
* @param {string} [additional] The additional text for the message data
* @param {string} [type] The node type (defaults to "Identifier")
* @returns {Object} An expected error object
*/
function definedError(varName, additional = "", type = "Identifier") {
return {
messageId: "unusedVar",
data: {
varName,
action: "defined",
additional
},
type
};
}
/**
* Returns an expected error for assigned-but-not-used variables.
* @param {string} varName The name of the variable
* @param {string} [additional] The additional text for the message data
* @param {string} [type] The node type (defaults to "Identifier")
* @returns {Object} An expected error object
*/
function assignedError(varName, additional = "", type = "Identifier") {
return {
messageId: "unusedVar",
data: {
varName,
action: "assigned a value",
additional
},
type
};
}
ruleTester.run("no-unused-vars", rule, {
valid: [
"var foo = 5;\n\nlabel: while (true) {\n console.log(foo);\n break label;\n}",
"var foo = 5;\n\nwhile (true) {\n console.log(foo);\n break;\n}",
{ code: "for (let prop in box) {\n box[prop] = parseInt(box[prop]);\n}", languageOptions: { ecmaVersion: 6 } },
"var box = {a: 2};\n for (var prop in box) {\n box[prop] = parseInt(box[prop]);\n}",
"f({ set foo(a) { return; } });",
{ code: "a; var a;", options: ["all"] },
{ code: "var a=10; alert(a);", options: ["all"] },
{ code: "var a=10; (function() { alert(a); })();", options: ["all"] },
{ code: "var a=10; (function() { setTimeout(function() { alert(a); }, 0); })();", options: ["all"] },
{ code: "var a=10; d[a] = 0;", options: ["all"] },
{ code: "(function() { var a=10; return a; })();", options: ["all"] },
{ code: "(function g() {})()", options: ["all"] },
{ code: "function f(a) {alert(a);}; f();", options: ["all"] },
{ code: "var c = 0; function f(a){ var b = a; return b; }; f(c);", options: ["all"] },
{ code: "function a(x, y){ return y; }; a();", options: ["all"] },
{ code: "var arr1 = [1, 2]; var arr2 = [3, 4]; for (var i in arr1) { arr1[i] = 5; } for (var i in arr2) { arr2[i] = 10; }", options: ["all"] },
{ code: "var a=10;", options: ["local"] },
{ code: "var min = \"min\"; Math[min];", options: ["all"] },
{ code: "Foo.bar = function(baz) { return baz; };", options: ["all"] },
"myFunc(function foo() {}.bind(this))",
"myFunc(function foo(){}.toString())",
"function foo(first, second) {\ndoStuff(function() {\nconsole.log(second);});}; foo()",
"(function() { var doSomething = function doSomething() {}; doSomething() }())",
"/*global a */ a;",
{ code: "var a=10; (function() { alert(a); })();", options: [{ vars: "all" }] },
{ code: "function g(bar, baz) { return baz; }; g();", options: [{ vars: "all" }] },
{ code: "function g(bar, baz) { return baz; }; g();", options: [{ vars: "all", args: "after-used" }] },
{ code: "function g(bar, baz) { return bar; }; g();", options: [{ vars: "all", args: "none" }] },
{ code: "function g(bar, baz) { return 2; }; g();", options: [{ vars: "all", args: "none" }] },
{ code: "function g(bar, baz) { return bar + baz; }; g();", options: [{ vars: "local", args: "all" }] },
{ code: "var g = function(bar, baz) { return 2; }; g();", options: [{ vars: "all", args: "none" }] },
"(function z() { z(); })();",
{ code: " ", languageOptions: { globals: { a: true } } },
{ code: "var who = \"Paul\";\nmodule.exports = `Hello ${who}!`;", languageOptions: { ecmaVersion: 6 } },
{ code: "export var foo = 123;", languageOptions: { ecmaVersion: 6, sourceType: "module" } },
{ code: "export function foo () {}", languageOptions: { ecmaVersion: 6, sourceType: "module" } },
{ code: "let toUpper = (partial) => partial.toUpperCase; export {toUpper}", languageOptions: { ecmaVersion: 6, sourceType: "module" } },
{ code: "export class foo {}", languageOptions: { ecmaVersion: 6, sourceType: "module" } },
{ code: "class Foo{}; var x = new Foo(); x.foo()", languageOptions: { ecmaVersion: 6 } },
{ code: "const foo = \"hello!\";function bar(foobar = foo) { foobar.replace(/!$/, \" world!\");}\nbar();", languageOptions: { ecmaVersion: 6 } },
"function Foo(){}; var x = new Foo(); x.foo()",
"function foo() {var foo = 1; return foo}; foo();",
"function foo(foo) {return foo}; foo(1);",
"function foo() {function foo() {return 1;}; return foo()}; foo();",
{ code: "function foo() {var foo = 1; return foo}; foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "function foo(foo) {return foo}; foo(1);", languageOptions: { ecmaVersion: 6 } },
{ code: "function foo() {function foo() {return 1;}; return foo()}; foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; const [y = x] = []; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; const {y = x} = {}; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; const {z: [y = x]} = {}; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = []; const {z: [y] = x} = {}; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; let y; [y = x] = []; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; let y; ({z: [y = x]} = {}); foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = []; let y; ({z: [y] = x} = {}); foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; function foo(y = x) { bar(y); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; function foo({y = x} = {}) { bar(y); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; function foo(y = function(z = x) { bar(z); }) { y(); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "const x = 1; function foo(y = function() { bar(x); }) { y(); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; var [y = x] = []; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; var {y = x} = {}; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; var {z: [y = x]} = {}; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = []; var {z: [y] = x} = {}; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1, y; [y = x] = []; foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1, y; ({z: [y = x]} = {}); foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = [], y; ({z: [y] = x} = {}); foo(y);", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; function foo(y = x) { bar(y); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; function foo({y = x} = {}) { bar(y); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; function foo(y = function(z = x) { bar(z); }) { y(); } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "var x = 1; function foo(y = function() { bar(x); }) { y(); } foo();", languageOptions: { ecmaVersion: 6 } },
// exported variables should work
"/*exported toaster*/ var toaster = 'great'",
"/*exported toaster, poster*/ var toaster = 1; poster = 0;",
{ code: "/*exported x*/ var { x } = y", languageOptions: { ecmaVersion: 6 } },
{ code: "/*exported x, y*/ var { x, y } = z", languageOptions: { ecmaVersion: 6 } },
// Can mark variables as used via context.markVariableAsUsed()
"/*eslint custom/use-every-a:1*/ var a;",
"/*eslint custom/use-every-a:1*/ !function(a) { return 1; }",
"/*eslint custom/use-every-a:1*/ !function() { var a; return 1 }",
// ignore pattern
{ code: "var _a;", options: [{ vars: "all", varsIgnorePattern: "^_" }] },
{ code: "var a; function foo() { var _b; } foo();", options: [{ vars: "local", varsIgnorePattern: "^_" }] },
{ code: "function foo(_a) { } foo();", options: [{ args: "all", argsIgnorePattern: "^_" }] },
{ code: "function foo(a, _b) { return a; } foo();", options: [{ args: "after-used", argsIgnorePattern: "^_" }] },
{ code: "var [ firstItemIgnored, secondItem ] = items;\nconsole.log(secondItem);", options: [{ vars: "all", varsIgnorePattern: "[iI]gnored" }], languageOptions: { ecmaVersion: 6 } },
{
code: "const [ a, _b, c ] = items;\nconsole.log(a+c);",
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: "const [ [a, _b, c] ] = items;\nconsole.log(a+c);",
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: "const { x: [_a, foo] } = bar;\nconsole.log(foo);",
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: "function baz([_b, foo]) { foo; };\nbaz()",
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: "function baz({x: [_b, foo]}) {foo};\nbaz()",
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: "function baz([{x: [_b, foo]}]) {foo};\nbaz()",
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: `
let _a, b;
foo.forEach(item => {
[_a, b] = item;
doSomething(b);
});
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: `
// doesn't report _x
let _x, y;
_x = 1;
[_x, y] = foo;
y;
// doesn't report _a
let _a, b;
[_a, b] = foo;
_a = 1;
b;
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 2018 }
},
{
code: `
// doesn't report _x
let _x, y;
_x = 1;
[_x, y] = foo;
y;
// doesn't report _a
let _a, b;
_a = 1;
({_a, ...b } = foo);
b;
`,
options: [{ destructuredArrayIgnorePattern: "^_", ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2018 }
},
// for-in loops (see #2342)
"(function(obj) { var name; for ( name in obj ) return; })({});",
"(function(obj) { var name; for ( name in obj ) { return; } })({});",
"(function(obj) { for ( var name in obj ) { return true } })({})",
"(function(obj) { for ( var name in obj ) return true })({})",
{ code: "(function(obj) { let name; for ( name in obj ) return; })({});", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(obj) { let name; for ( name in obj ) { return; } })({});", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(obj) { for ( let name in obj ) { return true } })({})", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(obj) { for ( let name in obj ) return true })({})", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(obj) { for ( const name in obj ) { return true } })({})", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(obj) { for ( const name in obj ) return true })({})", languageOptions: { ecmaVersion: 6 } },
// For-of loops
{ code: "(function(iter) { let name; for ( name of iter ) return; })({});", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(iter) { let name; for ( name of iter ) { return; } })({});", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(iter) { for ( let name of iter ) { return true } })({})", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(iter) { for ( let name of iter ) return true })({})", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(iter) { for ( const name of iter ) { return true } })({})", languageOptions: { ecmaVersion: 6 } },
{ code: "(function(iter) { for ( const name of iter ) return true })({})", languageOptions: { ecmaVersion: 6 } },
// Sequence Expressions (See https://github.com/eslint/eslint/issues/14325)
{ code: "let x = 0; foo = (0, x++);", languageOptions: { ecmaVersion: 6 } },
{ code: "let x = 0; foo = (0, x += 1);", languageOptions: { ecmaVersion: 6 } },
{ code: "let x = 0; foo = (0, x = x + 1);", languageOptions: { ecmaVersion: 6 } },
// caughtErrors
{
code: "try{}catch(err){}",
options: [{ caughtErrors: "none" }]
},
{
code: "try{}catch(err){console.error(err);}",
options: [{ caughtErrors: "all" }]
},
{
code: "try{}catch(ignoreErr){}",
options: [{ caughtErrorsIgnorePattern: "^ignore" }]
},
{
code: "try{}catch(ignoreErr){}",
options: [{ caughtErrors: "all", caughtErrorsIgnorePattern: "^ignore" }]
},
// caughtErrors with other combinations
{
code: "try{}catch(err){}",
options: [{ caughtErrors: "none", vars: "all", args: "all" }]
},
// Using object rest for variable omission
{
code: "const data = { type: 'coords', x: 1, y: 2 };\nconst { type, ...coords } = data;\n console.log(coords);",
options: [{ ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2018 }
},
// https://github.com/eslint/eslint/issues/6348
"var a = 0, b; b = a = a + 1; foo(b);",
"var a = 0, b; b = a += a + 1; foo(b);",
"var a = 0, b; b = a++; foo(b);",
"function foo(a) { var b = a = a + 1; bar(b) } foo();",
"function foo(a) { var b = a += a + 1; bar(b) } foo();",
"function foo(a) { var b = a++; bar(b) } foo();",
// https://github.com/eslint/eslint/issues/6576
[
"var unregisterFooWatcher;",
"// ...",
"unregisterFooWatcher = $scope.$watch( \"foo\", function() {",
" // ...some code..",
" unregisterFooWatcher();",
"});"
].join("\n"),
[
"var ref;",
"ref = setInterval(",
" function(){",
" clearInterval(ref);",
" }, 10);"
].join("\n"),
[
"var _timer;",
"function f() {",
" _timer = setTimeout(function () {}, _timer ? 100 : 0);",
"}",
"f();"
].join("\n"),
"function foo(cb) { cb = function() { function something(a) { cb(1 + a); } register(something); }(); } foo();",
{ code: "function* foo(cb) { cb = yield function(a) { cb(1 + a); }; } foo();", languageOptions: { ecmaVersion: 6 } },
{ code: "function foo(cb) { cb = tag`hello${function(a) { cb(1 + a); }}`; } foo();", languageOptions: { ecmaVersion: 6 } },
"function foo(cb) { var b; cb = b = function(a) { cb(1 + a); }; b(); } foo();",
// https://github.com/eslint/eslint/issues/6646
[
"function someFunction() {",
" var a = 0, i;",
" for (i = 0; i < 2; i++) {",
" a = myFunction(a);",
" }",
"}",
"someFunction();"
].join("\n"),
// https://github.com/eslint/eslint/issues/7124
{
code: "(function(a, b, {c, d}) { d })",
options: [{ argsIgnorePattern: "c" }],
languageOptions: { ecmaVersion: 6 }
},
{
code: "(function(a, b, {c, d}) { c })",
options: [{ argsIgnorePattern: "d" }],
languageOptions: { ecmaVersion: 6 }
},
// https://github.com/eslint/eslint/issues/7250
{
code: "(function(a, b, c) { c })",
options: [{ argsIgnorePattern: "c" }]
},
{
code: "(function(a, b, {c, d}) { c })",
options: [{ argsIgnorePattern: "[cd]" }],
languageOptions: { ecmaVersion: 6 }
},
// https://github.com/eslint/eslint/issues/7351
{
code: "(class { set foo(UNUSED) {} })",
languageOptions: { ecmaVersion: 6 }
},
{
code: "class Foo { set bar(UNUSED) {} } console.log(Foo)",
languageOptions: { ecmaVersion: 6 }
},
// https://github.com/eslint/eslint/issues/8119
{
code: "(({a, ...rest}) => rest)",
options: [{ args: "all", ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2018 }
},
// https://github.com/eslint/eslint/issues/14163
{
code: "let foo, rest;\n({ foo, ...rest } = something);\nconsole.log(rest);",
options: [{ ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2020 }
},
// https://github.com/eslint/eslint/issues/10952
"/*eslint custom/use-every-a:1*/ !function(b, a) { return 1 }",
// https://github.com/eslint/eslint/issues/10982
"var a = function () { a(); }; a();",
"var a = function(){ return function () { a(); } }; a();",
{
code: "const a = () => { a(); }; a();",
languageOptions: { ecmaVersion: 2015 }
},
{
code: "const a = () => () => { a(); }; a();",
languageOptions: { ecmaVersion: 2015 }
},
// export * as ns from "source"
{
code: 'export * as ns from "source"',
languageOptions: { ecmaVersion: 2020, sourceType: "module" }
},
// import.meta
{
code: "import.meta",
languageOptions: { ecmaVersion: 2020, sourceType: "module" }
},
// https://github.com/eslint/eslint/issues/17299
{
code: "var a; a ||= 1;",
languageOptions: { ecmaVersion: 2021 }
},
{
code: "var a; a &&= 1;",
languageOptions: { ecmaVersion: 2021 }
},
{
code: "var a; a ??= 1;",
languageOptions: { ecmaVersion: 2021 }
}
],
invalid: [
{ code: "function foox() { return foox(); }", errors: [definedError("foox")] },
{ code: "(function() { function foox() { if (true) { return foox(); } } }())", errors: [definedError("foox")] },
{ code: "var a=10", errors: [assignedError("a")] },
{ code: "function f() { var a = 1; return function(){ f(a *= 2); }; }", errors: [definedError("f")] },
{ code: "function f() { var a = 1; return function(){ f(++a); }; }", errors: [definedError("f")] },
{ code: "/*global a */", errors: [definedError("a", "", "Program")] },
{ code: "function foo(first, second) {\ndoStuff(function() {\nconsole.log(second);});};", errors: [definedError("foo")] },
{ code: "var a=10;", options: ["all"], errors: [assignedError("a")] },
{ code: "var a=10; a=20;", options: ["all"], errors: [assignedError("a")] },
{ code: "var a=10; (function() { var a = 1; alert(a); })();", options: ["all"], errors: [assignedError("a")] },
{ code: "var a=10, b=0, c=null; alert(a+b)", options: ["all"], errors: [assignedError("c")] },
{ code: "var a=10, b=0, c=null; setTimeout(function() { var b=2; alert(a+b+c); }, 0);", options: ["all"], errors: [assignedError("b")] },
{ code: "var a=10, b=0, c=null; setTimeout(function() { var b=2; var c=2; alert(a+b+c); }, 0);", options: ["all"], errors: [assignedError("b"), assignedError("c")] },
{ code: "function f(){var a=[];return a.map(function(){});}", options: ["all"], errors: [definedError("f")] },
{ code: "function f(){var a=[];return a.map(function g(){});}", options: ["all"], errors: [definedError("f")] },
{
code: "function foo() {function foo(x) {\nreturn x; }; return function() {return foo; }; }",
errors: [{
messageId: "unusedVar",
data: { varName: "foo", action: "defined", additional: "" },
line: 1,
type: "Identifier"
}]
},
{ code: "function f(){var x;function a(){x=42;}function b(){alert(x);}}", options: ["all"], errors: 3 },
{ code: "function f(a) {}; f();", options: ["all"], errors: [definedError("a")] },
{ code: "function a(x, y, z){ return y; }; a();", options: ["all"], errors: [definedError("z")] },
{ code: "var min = Math.min", options: ["all"], errors: [assignedError("min")] },
{ code: "var min = {min: 1}", options: ["all"], errors: [assignedError("min")] },
{ code: "Foo.bar = function(baz) { return 1; };", options: ["all"], errors: [definedError("baz")] },
{ code: "var min = {min: 1}", options: [{ vars: "all" }], errors: [assignedError("min")] },
{ code: "function gg(baz, bar) { return baz; }; gg();", options: [{ vars: "all" }], errors: [definedError("bar")] },
{ code: "(function(foo, baz, bar) { return baz; })();", options: [{ vars: "all", args: "after-used" }], errors: [definedError("bar")] },
{ code: "(function(foo, baz, bar) { return baz; })();", options: [{ vars: "all", args: "all" }], errors: [definedError("foo"), definedError("bar")] },
{ code: "(function z(foo) { var bar = 33; })();", options: [{ vars: "all", args: "all" }], errors: [definedError("foo"), assignedError("bar")] },
{ code: "(function z(foo) { z(); })();", options: [{}], errors: [definedError("foo")] },
{ code: "function f() { var a = 1; return function(){ f(a = 2); }; }", options: [{}], errors: [definedError("f"), assignedError("a")] },
{ code: "import x from \"y\";", languageOptions: { ecmaVersion: 6, sourceType: "module" }, errors: [definedError("x")] },
{ code: "export function fn2({ x, y }) {\n console.log(x); \n};", languageOptions: { ecmaVersion: 6, sourceType: "module" }, errors: [definedError("y")] },
{ code: "export function fn2( x, y ) {\n console.log(x); \n};", languageOptions: { ecmaVersion: 6, sourceType: "module" }, errors: [definedError("y")] },
// exported
{ code: "/*exported max*/ var max = 1, min = {min: 1}", errors: [assignedError("min")] },
{ code: "/*exported x*/ var { x, y } = z", languageOptions: { ecmaVersion: 6 }, errors: [assignedError("y")] },
// ignore pattern
{
code: "var _a; var b;",
options: [{ vars: "all", varsIgnorePattern: "^_" }],
errors: [{
line: 1,
column: 13,
messageId: "unusedVar",
data: {
varName: "b",
action: "defined",
additional: ". Allowed unused vars must match /^_/u"
}
}]
},
{
code: "var a; function foo() { var _b; var c_; } foo();",
options: [{ vars: "local", varsIgnorePattern: "^_" }],
errors: [{
line: 1,
column: 37,
messageId: "unusedVar",
data: {
varName: "c_",
action: "defined",
additional: ". Allowed unused vars must match /^_/u"
}
}]
},
{
code: "function foo(a, _b) { } foo();",
options: [{ args: "all", argsIgnorePattern: "^_" }],
errors: [{
line: 1,
column: 14,
messageId: "unusedVar",
data: {
varName: "a",
action: "defined",
additional: ". Allowed unused args must match /^_/u"
}
}]
},
{
code: "function foo(a, _b, c) { return a; } foo();",
options: [{ args: "after-used", argsIgnorePattern: "^_" }],
errors: [{
line: 1,
column: 21,
messageId: "unusedVar",
data: {
varName: "c",
action: "defined",
additional: ". Allowed unused args must match /^_/u"
}
}]
},
{
code: "function foo(_a) { } foo();",
options: [{ args: "all", argsIgnorePattern: "[iI]gnored" }],
errors: [{
line: 1,
column: 14,
messageId: "unusedVar",
data: {
varName: "_a",
action: "defined",
additional: ". Allowed unused args must match /[iI]gnored/u"
}
}]
},
{
code: "var [ firstItemIgnored, secondItem ] = items;",
options: [{ vars: "all", varsIgnorePattern: "[iI]gnored" }],
languageOptions: { ecmaVersion: 6 },
errors: [{
line: 1,
column: 25,
messageId: "unusedVar",
data: {
varName: "secondItem",
action: "assigned a value",
additional: ". Allowed unused vars must match /[iI]gnored/u"
}
}]
},
// https://github.com/eslint/eslint/issues/15611
{
code: `
const array = ['a', 'b', 'c'];
const [a, _b, c] = array;
const newArray = [a, c];
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 2020 },
errors: [
// should report only `newArray`
{ ...assignedError("newArray"), line: 4, column: 19 }
]
},
{
code: `
const array = ['a', 'b', 'c', 'd', 'e'];
const [a, _b, c] = array;
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 2020 },
errors: [
{
...assignedError("a", ". Allowed unused elements of array destructuring patterns must match /^_/u"),
line: 3,
column: 20
},
{
...assignedError("c", ". Allowed unused elements of array destructuring patterns must match /^_/u"),
line: 3,
column: 27
}
]
},
{
code: `
const array = ['a', 'b', 'c'];
const [a, _b, c] = array;
const fooArray = ['foo'];
const barArray = ['bar'];
const ignoreArray = ['ignore'];
`,
options: [{ destructuredArrayIgnorePattern: "^_", varsIgnorePattern: "ignore" }],
languageOptions: { ecmaVersion: 2020 },
errors: [
{
...assignedError("a", ". Allowed unused elements of array destructuring patterns must match /^_/u"),
line: 3,
column: 20
},
{
...assignedError("c", ". Allowed unused elements of array destructuring patterns must match /^_/u"),
line: 3,
column: 27
},
{
...assignedError("fooArray", ". Allowed unused vars must match /ignore/u"),
line: 4,
column: 19
},
{
...assignedError("barArray", ". Allowed unused vars must match /ignore/u"),
line: 5,
column: 19
}
]
},
{
code: `
const array = [obj];
const [{_a, foo}] = array;
console.log(foo);
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 2020 },
errors: [
{
...assignedError("_a"),
line: 3,
column: 21
}
]
},
{
code: `
function foo([{_a, bar}]) {
bar;
}
foo();
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 2020 },
errors: [
{
...definedError("_a"),
line: 2,
column: 28
}
]
},
{
code: `
let _a, b;
foo.forEach(item => {
[a, b] = item;
});
`,
options: [{ destructuredArrayIgnorePattern: "^_" }],
languageOptions: { ecmaVersion: 2020 },
errors: [
{
...definedError("_a"),
line: 2,
column: 17
},
{
...assignedError("b"),
line: 2,
column: 21
}
]
},
// for-in loops (see #2342)
{
code: "(function(obj) { var name; for ( name in obj ) { i(); return; } })({});",
errors: [{
line: 1,
column: 34,
messageId: "unusedVar",
data: {
varName: "name",
action: "assigned a value",
additional: ""
}
}]
},
{
code: "(function(obj) { var name; for ( name in obj ) { } })({});",
errors: [{
line: 1,
column: 34,
messageId: "unusedVar",
data: {
varName: "name",
action: "assigned a value",
additional: ""
}
}]
},
{
code: "(function(obj) { for ( var name in obj ) { } })({});",
errors: [{
line: 1,
column: 28,
messageId: "unusedVar",
data: {
varName: "name",
action: "assigned a value",
additional: ""
}
}]
},
// For-of loops
{
code: "(function(iter) { var name; for ( name of iter ) { i(); return; } })({});",
languageOptions: { ecmaVersion: 6 },
errors: [{
line: 1,
column: 35,
messageId: "unusedVar",
data: {
varName: "name",
action: "assigned a value",
additional: ""
}
}]
},
{
code: "(function(iter) { var name; for ( name of iter ) { } })({});",
languageOptions: { ecmaVersion: 6 },
errors: [{
line: 1,
column: 35,
messageId: "unusedVar",
data: {
varName: "name",
action: "assigned a value",
additional: ""
}
}]
},
{
code: "(function(iter) { for ( var name of iter ) { } })({});",
languageOptions: { ecmaVersion: 6 },
errors: [{
line: 1,
column: 29,
messageId: "unusedVar",
data: {
varName: "name",
action: "assigned a value",
additional: ""
}
}]
},
// https://github.com/eslint/eslint/issues/3617
{
code: "\n/* global foobar, foo, bar */\nfoobar;",
errors: [
{
line: 2,
endLine: 2,
column: 19,
endColumn: 22,
messageId: "unusedVar",
data: {
varName: "foo",
action: "defined",
additional: ""
}
},
{
line: 2,
endLine: 2,
column: 24,
endColumn: 27,
messageId: "unusedVar",
data: {
varName: "bar",
action: "defined",
additional: ""
}
}
]
},
{
code: "\n/* global foobar,\n foo,\n bar\n */\nfoobar;",
errors: [
{
line: 3,
column: 4,
endLine: 3,
endColumn: 7,
messageId: "unusedVar",
data: {
varName: "foo",
action: "defined",
additional: ""
}
},
{
line: 4,
column: 4,
endLine: 4,
endColumn: 7,
messageId: "unusedVar",
data: {
varName: "bar",
action: "defined",
additional: ""
}
}
]
},
// Rest property sibling without ignoreRestSiblings
{
code: "const data = { type: 'coords', x: 1, y: 2 };\nconst { type, ...coords } = data;\n console.log(coords);",
languageOptions: { ecmaVersion: 2018 },
errors: [
{
line: 2,
column: 9,
messageId: "unusedVar",
data: {
varName: "type",
action: "assigned a value",
additional: ""
}
}
]
},
// Unused rest property with ignoreRestSiblings
{
code: "const data = { type: 'coords', x: 2, y: 2 };\nconst { type, ...coords } = data;\n console.log(type)",
options: [{ ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2018 },
errors: [
{
line: 2,
column: 18,
messageId: "unusedVar",
data: {
varName: "coords",
action: "assigned a value",
additional: ""
}
}
]
},
{
code: "let type, coords;\n({ type, ...coords } = data);\n console.log(type)",
options: [{ ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2018 },
errors: [
{
line: 2,
column: 13,
messageId: "unusedVar",
data: {
varName: "coords",
action: "assigned a value",
additional: ""
}
}
]
},
// Unused rest property without ignoreRestSiblings
{
code: "const data = { type: 'coords', x: 3, y: 2 };\nconst { type, ...coords } = data;\n console.log(type)",
languageOptions: { ecmaVersion: 2018 },
errors: [
{
line: 2,
column: 18,
messageId: "unusedVar",
data: {
varName: "coords",
action: "assigned a value",
additional: ""
}
}
]
},
// Nested array destructuring with rest property
{
code: "const data = { vars: ['x','y'], x: 1, y: 2 };\nconst { vars: [x], ...coords } = data;\n console.log(coords)",
languageOptions: { ecmaVersion: 2018 },
errors: [
{
line: 2,
column: 16,
messageId: "unusedVar",
data: {
varName: "x",
action: "assigned a value",
additional: ""
}
}
]
},
// Nested object destructuring with rest property
{
code: "const data = { defaults: { x: 0 }, x: 1, y: 2 };\nconst { defaults: { x }, ...coords } = data;\n console.log(coords)",
languageOptions: { ecmaVersion: 2018 },
errors: [
{
line: 2,
column: 21,
messageId: "unusedVar",
data: {
varName: "x",
action: "assigned a value",
additional: ""
}
}
]
},
// https://github.com/eslint/eslint/issues/8119
{
code: "(({a, ...rest}) => {})",
options: [{ args: "all", ignoreRestSiblings: true }],
languageOptions: { ecmaVersion: 2018 },
errors: [definedError("rest")]
},
// https://github.com/eslint/eslint/issues/3714
{
code: "/* global a$fooz,$foo */\na$fooz;",
errors: [
{
line: 1,
column: 18,
endLine: 1,
endColumn: 22,
messageId: "unusedVar",
data: {
varName: "$foo",
action: "defined",
additional: ""
}
}
]
},
{
code: "/* globals a$fooz, $ */\na$fooz;",
errors: [
{
line: 1,
column: 20,
endLine: 1,
endColumn: 21,
messageId: "unusedVar",
data: {
varName: "$",
action: "defined",
additional: ""
}