RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-23 19:05:08 +00:00
Code Issues Activity Actions

LibJS: Function declarations in if statement clauses

Browse source 
https://tc39.es/ecma262/#sec-functiondeclarations-in-ifstatement-statement-clauses

B.3.4 FunctionDeclarations in IfStatement Statement Clauses

The following augments the IfStatement production in 13.6:

    IfStatement[Yield, Await, Return] :
        if ( Expression[+In, ?Yield, ?Await] ) FunctionDeclaration[?Yield, ?Await, ~Default] else Statement[?Yield, ?Await, ?Return]
        if ( Expression[+In, ?Yield, ?Await] ) Statement[?Yield, ?Await, ?Return] else FunctionDeclaration[?Yield, ?Await, ~Default]
        if ( Expression[+In, ?Yield, ?Await] ) FunctionDeclaration[?Yield, ?Await, ~Default] else FunctionDeclaration[?Yield, ?Await, ~Default]
        if ( Expression[+In, ?Yield, ?Await] ) FunctionDeclaration[?Yield, ?Await, ~Default]

This production only applies when parsing non-strict code. Code matching
this production is processed as if each matching occurrence of
FunctionDeclaration[?Yield, ?Await, ~Default] was the sole
StatementListItem of a BlockStatement occupying that position in the
source code. The semantics of such a synthetic BlockStatement includes
the web legacy compatibility semantics specified in B.3.3.
This commit is contained in:
Linus Groh 2020-10-31 13:37:09 +00:00 • committed by Andreas Kling
parent 778011dac6
commit a598a2c19d
2 changed files with 66 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

41
Libraries/LibJS/Tests/if-statement-function-declaration.js Normal file
View file

@ -0,0 +1,41 @@
describe("function declarations in if statement clauses", () => {
test("if clause", () => {
if (true) function foo() {}
if (false) function bar() {}
expect(typeof globalThis.foo).toBe("function");
expect(typeof globalThis.bar).toBe("undefined");
});
test("else clause", () => {
if (false);
else function foo() {}
if (true);
else function bar() {}
expect(typeof globalThis.foo).toBe("function");
expect(typeof globalThis.bar).toBe("undefined");
});
test("if and else clause", () => {
if (true) function foo() {}
else function bar() {}
expect(typeof globalThis.foo).toBe("function");
expect(typeof globalThis.bar).toBe("undefined");
});
test("syntax error in strict mode", () => {
expect(`
"use strict";
if (true) function foo() {}
`).not.toEval();
expect(`
"use strict";
if (false);
else function foo() {}
`).not.toEval();
expect(`
"use strict";
if (false) function foo() {}
else function bar() {}
`).not.toEval();
});
});