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/
no-unused-expressions.js
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/
no-unused-expressions.js
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/**
* @fileoverview Tests for no-unused-expressions rule.
* @author Michael Ficarra
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const rule = require("../../../lib/rules/no-unused-expressions"),
{ RuleTester } = require("../../../lib/rule-tester");
//------------------------------------------------------------------------------
// Tests
//------------------------------------------------------------------------------
const ruleTester = new RuleTester();
ruleTester.run("no-unused-expressions", rule, {
valid: [
"function f(){}",
"a = b",
"new a",
"{}",
"f(); g()",
"i++",
"a()",
{ code: "a && a()", options: [{ allowShortCircuit: true }] },
{ code: "a() || (b = c)", options: [{ allowShortCircuit: true }] },
{ code: "a ? b() : c()", options: [{ allowTernary: true }] },
{ code: "a ? b() || (c = d) : e()", options: [{ allowShortCircuit: true, allowTernary: true }] },
"delete foo.bar",
"void new C",
"\"use strict\";",
"\"directive one\"; \"directive two\"; f();",
"function foo() {\"use strict\"; return true; }",
{ code: "var foo = () => {\"use strict\"; return true; }", parserOptions: { ecmaVersion: 6 } },
"function foo() {\"directive one\"; \"directive two\"; f(); }",
"function foo() { var foo = \"use strict\"; return true; }",
{
code: "function* foo(){ yield 0; }",
parserOptions: { ecmaVersion: 6 }
},
{
code: "async function foo() { await 5; }",
parserOptions: { ecmaVersion: 8 }
},
{
code: "async function foo() { await foo.bar; }",
parserOptions: { ecmaVersion: 8 }
},
{
code: "async function foo() { bar && await baz; }",
options: [{ allowShortCircuit: true }],
parserOptions: { ecmaVersion: 8 }
},
{
code: "async function foo() { foo ? await bar : await baz; }",
options: [{ allowTernary: true }],
parserOptions: { ecmaVersion: 8 }
},
{
code: "tag`tagged template literal`",
options: [{ allowTaggedTemplates: true }],
parserOptions: { ecmaVersion: 6 }
},
{
code: "shouldNotBeAffectedByAllowTemplateTagsOption()",
options: [{ allowTaggedTemplates: true }],
parserOptions: { ecmaVersion: 6 }
},
{
code: "import(\"foo\")",
parserOptions: { ecmaVersion: 11 }
},
{
code: "func?.(\"foo\")",
parserOptions: { ecmaVersion: 11 }
},
{
code: "obj?.foo(\"bar\")",
parserOptions: { ecmaVersion: 11 }
},
// JSX
{
code: "<div />",
parserOptions: { ecmaFeatures: { jsx: true } }
},
{
code: "var partial = <div />",
parserOptions: { ecmaFeatures: { jsx: true } }
}
],
invalid: [
{ code: "0", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "f(), 0", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "{0}", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "[]", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a && b();", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a() || false", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a || (b = c)", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a ? b() || (c = d) : e", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{
code: "`untagged template literal`",
parserOptions: { ecmaVersion: 6 },
errors: [{ messageId: "unusedExpression" }]
},
{
code: "tag`tagged template literal`",
parserOptions: { ecmaVersion: 6 },
errors: [{ messageId: "unusedExpression" }]
},
{ code: "a && b()", options: [{ allowTernary: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a ? b() : c()", options: [{ allowShortCircuit: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a || b", options: [{ allowShortCircuit: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a() && b", options: [{ allowShortCircuit: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a ? b : 0", options: [{ allowTernary: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "a ? b : c()", options: [{ allowTernary: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "foo.bar;", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "!a", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "+a", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "\"directive one\"; f(); \"directive two\";", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "function foo() {\"directive one\"; f(); \"directive two\"; }", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "if (0) { \"not a directive\"; f(); }", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "function foo() { var foo = true; \"use strict\"; }", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{ code: "var foo = () => { var foo = true; \"use strict\"; }", parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
{
code: "`untagged template literal`",
options: [{ allowTaggedTemplates: true }],
parserOptions: { ecmaVersion: 6 },
errors: [{ messageId: "unusedExpression" }]
},
{
code: "`untagged template literal`",
options: [{ allowTaggedTemplates: false }],
parserOptions: { ecmaVersion: 6 },
errors: [{ messageId: "unusedExpression" }]
},
{
code: "tag`tagged template literal`",
options: [{ allowTaggedTemplates: false }],
parserOptions: { ecmaVersion: 6 },
errors: [{ messageId: "unusedExpression" }]
},
// Optional chaining
{
code: "obj?.foo",
parserOptions: { ecmaVersion: 2020 },
errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
},
{
code: "obj?.foo.bar",
parserOptions: { ecmaVersion: 2020 },
errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
},
{
code: "obj?.foo().bar",
parserOptions: { ecmaVersion: 2020 },
errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
},
// JSX
{
code: "<div />",
options: [{ disallowJSX: true }],
parserOptions: { ecmaFeatures: { jsx: true } },
errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
}
]
});