Warning: unreachable code after return statement
The JavaScript warning "unreachable code after return statement" occurs when using anexpression after areturn statement, or when using asemicolon-less return statement but including an expression directly after.
Message
Warning: unreachable code after return statement (Firefox)
Error type
Warning
What went wrong?
Unreachable code after a return statement might occur in these situations:
- When using an expression after a
returnstatement, or - when using a semicolon-less return statement but including an expression directlyafter.
When an expression exists after a validreturn statement, a warning isgiven to indicate that the code after thereturn statement is unreachable,meaning it can never be run.
Why should I have semicolons afterreturn statements? In the case ofsemicolon-lessreturn statements, it can be unclear whether the developerintended to return the statement on the following line, or to stop execution and return.The warning indicates that there is ambiguity in the way thereturnstatement is written.
Warnings will not be shown for semicolon-less returns if these statements follow it:
Examples
Invalid cases
function f() { let x = 3; x += 4; return x; // return exits the function immediately x -= 3; // so this line will never run; it is unreachable}function g() { return // this is treated like `return;` 3 + 4; // so the function returns, and this line is never reached}Valid cases
function f() { let x = 3; x += 4; x -= 3; return x; // OK: return after all other statements}function g() { return 3 + 4 // OK: semicolon-less return with expression on the same line}