/
no-unreachable.js
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/
no-unreachable.js
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/**
* @fileoverview Tests for no-unreachable rule.
* @author Joel Feenstra
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const rule = require("../../../lib/rules/no-unreachable"),
{ RuleTester } = require("../../../lib/rule-tester");
//------------------------------------------------------------------------------
// Tests
//------------------------------------------------------------------------------
const ruleTester = new RuleTester();
ruleTester.run("no-unreachable", rule, {
valid: [
"function foo() { function bar() { return 1; } return bar(); }",
"function foo() { return bar(); function bar() { return 1; } }",
"function foo() { return x; var x; }",
"function foo() { var x = 1; var y = 2; }",
"function foo() { var x = 1; var y = 2; return; }",
"while (true) { switch (foo) { case 1: x = 1; x = 2;} }",
"while (true) { break; var x; }",
"while (true) { continue; var x, y; }",
"while (true) { throw 'message'; var x; }",
"while (true) { if (true) break; var x = 1; }",
"while (true) continue;",
"switch (foo) { case 1: break; var x; }",
"switch (foo) { case 1: break; var x; default: throw true; };",
{
code: "const arrow_direction = arrow => { switch (arrow) { default: throw new Error(); };}",
parserOptions: {
ecmaVersion: 6
}
},
"var x = 1; y = 2; throw 'uh oh'; var y;",
"function foo() { var x = 1; if (x) { return; } x = 2; }",
"function foo() { var x = 1; if (x) { } else { return; } x = 2; }",
"function foo() { var x = 1; switch (x) { case 0: break; default: return; } x = 2; }",
"function foo() { var x = 1; while (x) { return; } x = 2; }",
"function foo() { var x = 1; for (x in {}) { return; } x = 2; }",
"function foo() { var x = 1; try { return; } finally { x = 2; } }",
"function foo() { var x = 1; for (;;) { if (x) break; } x = 2; }",
"A: { break A; } foo()",
{
code: "function* foo() { try { yield 1; return; } catch (err) { return err; } }",
parserOptions: {
ecmaVersion: 6
}
},
{
code: "function foo() { try { bar(); return; } catch (err) { return err; } }",
parserOptions: {
ecmaVersion: 6
}
},
{
code: "function foo() { try { a.b.c = 1; return; } catch (err) { return err; } }",
parserOptions: {
ecmaVersion: 6
}
},
{
code: "class C { foo = reachable; }",
parserOptions: { ecmaVersion: 2022 }
},
{
code: "class C { foo = reachable; constructor() {} }",
parserOptions: { ecmaVersion: 2022 }
},
{
code: "class C extends B { foo = reachable; }",
parserOptions: { ecmaVersion: 2022 }
},
{
code: "class C extends B { foo = reachable; constructor() { super(); } }",
parserOptions: { ecmaVersion: 2022 }
},
{
code: "class C extends B { static foo = reachable; constructor() {} }",
parserOptions: { ecmaVersion: 2022 }
}
],
invalid: [
{ code: "function foo() { return x; var x = 1; }", errors: [{ messageId: "unreachableCode", type: "VariableDeclaration" }] },
{ code: "function foo() { return x; var x, y = 1; }", errors: [{ messageId: "unreachableCode", type: "VariableDeclaration" }] },
{ code: "while (true) { continue; var x = 1; }", errors: [{ messageId: "unreachableCode", type: "VariableDeclaration" }] },
{ code: "function foo() { return; x = 1; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { throw error; x = 1; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "while (true) { break; x = 1; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "while (true) { continue; x = 1; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { switch (foo) { case 1: return; x = 1; } }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { switch (foo) { case 1: throw e; x = 1; } }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "while (true) { switch (foo) { case 1: break; x = 1; } }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "while (true) { switch (foo) { case 1: continue; x = 1; } }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "var x = 1; throw 'uh oh'; var y = 2;", errors: [{ messageId: "unreachableCode", type: "VariableDeclaration" }] },
{ code: "function foo() { var x = 1; if (x) { return; } else { throw e; } x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; if (x) return; else throw -1; x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; try { return; } finally {} x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; try { } finally { return; } x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; do { return; } while (x); x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; while (x) { if (x) break; else continue; x = 2; } }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; for (;;) { if (x) continue; } x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{ code: "function foo() { var x = 1; while (true) { } x = 2; }", errors: [{ messageId: "unreachableCode", type: "ExpressionStatement" }] },
{
code: "const arrow_direction = arrow => { switch (arrow) { default: throw new Error(); }; g() }",
parserOptions: { ecmaVersion: 6 },
errors: [
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 1,
column: 86,
endLine: 1,
endColumn: 89
}
]
},
// Merge the warnings of continuous unreachable nodes.
{
code: `
function foo() {
return;
a(); // ← ERROR: Unreachable code. (no-unreachable)
b() // ↑ ';' token is included in the unreachable code, so this statement will be merged.
// comment
c(); // ↑ ')' token is included in the unreachable code, so this statement will be merged.
}
`,
errors: [
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 5,
column: 21,
endLine: 9,
endColumn: 25
}
]
},
{
code: `
function foo() {
return;
a();
if (b()) {
c()
} else {
d()
}
}
`,
errors: [
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 5,
column: 21,
endLine: 11,
endColumn: 22
}
]
},
{
code: `
function foo() {
if (a) {
return
b();
c();
} else {
throw err
d();
}
}
`,
errors: [
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 5,
column: 25,
endLine: 6,
endColumn: 29
},
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 9,
column: 25,
endLine: 9,
endColumn: 29
}
]
},
{
code: `
function foo() {
if (a) {
return
b();
c();
} else {
throw err
d();
}
e();
}
`,
errors: [
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 5,
column: 25,
endLine: 6,
endColumn: 29
},
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 9,
column: 25,
endLine: 9,
endColumn: 29
},
{
messageId: "unreachableCode",
type: "ExpressionStatement",
line: 11,
column: 21,
endLine: 11,
endColumn: 25
}
]
},
{
code: `
function* foo() {
try {
return;
} catch (err) {
return err;
}
}`,
parserOptions: {
ecmaVersion: 6
},
errors: [
{
messageId: "unreachableCode",
type: "BlockStatement",
line: 5,
column: 35,
endLine: 7,
endColumn: 22
}
]
},
{
code: `
function foo() {
try {
return;
} catch (err) {
return err;
}
}`,
parserOptions: {
ecmaVersion: 6
},
errors: [
{
messageId: "unreachableCode",
type: "BlockStatement",
line: 5,
column: 35,
endLine: 7,
endColumn: 22
}
]
},
{
code: `
function foo() {
try {
return;
let a = 1;
} catch (err) {
return err;
}
}`,
parserOptions: {
ecmaVersion: 6
},
errors: [
{
messageId: "unreachableCode",
type: "VariableDeclaration",
line: 5,
column: 25,
endLine: 5,
endColumn: 35
},
{
messageId: "unreachableCode",
type: "BlockStatement",
line: 6,
column: 35,
endLine: 8,
endColumn: 22
}
]
},
/*
* If `extends` exists, constructor exists, and the constructor doesn't
* contain `super()`, then the fields are unreachable because the
* evaluation of `super()` initializes fields in that case.
* In most cases, such an instantiation throws runtime errors, but
* doesn't throw if the constructor returns a value.
*/
{
code: "class C extends B { foo; constructor() {} }",
parserOptions: { ecmaVersion: 2022 },
errors: [{ messageId: "unreachableCode", column: 21, endColumn: 25 }]
},
{
code: "class C extends B { foo = unreachable + code; constructor() {} }",
parserOptions: { ecmaVersion: 2022 },
errors: [{ messageId: "unreachableCode", column: 21, endColumn: 46 }]
},
{
code: "class C extends B { foo; bar; constructor() {} }",
parserOptions: { ecmaVersion: 2022 },
errors: [{ messageId: "unreachableCode", column: 21, endColumn: 30 }]
},
{
code: "class C extends B { foo; constructor() {} bar; }",
parserOptions: { ecmaVersion: 2022 },
errors: [
{ messageId: "unreachableCode", column: 21, endColumn: 25 },
{ messageId: "unreachableCode", column: 43, endColumn: 47 }
]
},
{
code: "(class extends B { foo; constructor() {} bar; })",
parserOptions: { ecmaVersion: 2022 },
errors: [
{ messageId: "unreachableCode", column: 20, endColumn: 24 },
{ messageId: "unreachableCode", column: 42, endColumn: 46 }
]
},
{
code: "class B extends A { x; constructor() { class C extends D { [super().x]; constructor() {} } } }",
parserOptions: { ecmaVersion: 2022 },
errors: [
{ messageId: "unreachableCode", column: 60, endColumn: 72 }
]
},
{
code: "class B extends A { x; constructor() { class C extends super().x { y; constructor() {} } } }",
parserOptions: { ecmaVersion: 2022 },
errors: [
{ messageId: "unreachableCode", column: 68, endColumn: 70 }
]
},
{
code: "class B extends A { x; static y; z; static q; constructor() {} }",
parserOptions: { ecmaVersion: 2022 },
errors: [
{ messageId: "unreachableCode", column: 21, endColumn: 23 },
{ messageId: "unreachableCode", column: 34, endColumn: 36 }
]
}
]
});