What is the difference between yield and return inside a generator?

Q: What is the difference between yield and return inside a generator?

`yield` is used to produce intermediate values without terminating the generator; you can have many `yield` statements. `return` terminates the generator; the returned value is the final `value` and `done` becomes `true`. If no `return` is present, the generator implicitly returns `undefined`. After a `return`, the generator cannot be resumed.

Difficulty: 6/10

generators, yield vs return, iteration control

`yield` pauses the generator and can be called multiple times, while `return` ends the generator and sets `done: true`; further calls to `next()` return `{ done: true }`.

yield is used to produce intermediate values without terminating the generator; you can have many yield statements. return terminates the generator; the returned value is the final value and done becomes true. If no return is present, the generator implicitly returns undefined. After a return, the generator cannot be resumed.

Scenario Questions

0-2 years experience

2-5 years experience

1You have a function that streams lines from a large file using a generator. A teammate changed a `yield` to `return` to signal end-of-file, and the consumer now only gets the first line. Explain why this happened and how to fix it.

Follow-up Questions

What is the difference between yield and return inside a generator?

Difficulty: 6/10

generators, yield vs return, iteration control

`yield` pauses the generator and can be called multiple times, while `return` ends the generator and sets `done: true`; further calls to `next()` return `{ done: true }`.

Scenario Questions

0-2 years experience

2-5 years experience

1You have a function that streams lines from a large file using a generator. A teammate changed a `yield` to `return` to signal end-of-file, and the consumer now only gets the first line. Explain why this happened and how to fix it.

What is the difference between yield and return inside a generator?

yield pauses the generator and can be called multiple times, while return ends the generator and sets done: true; further calls to next() return { done: true }.

Scenario Questions

Follow-up Questions

What is the difference between yield and return inside a generator?

yield pauses the generator and can be called multiple times, while return ends the generator and sets done: true; further calls to next() return { done: true }.

Scenario Questions

Follow-up Questions

`yield` pauses the generator and can be called multiple times, while `return` ends the generator and sets `done: true`; further calls to `next()` return `{ done: true }`.

`yield` pauses the generator and can be called multiple times, while `return` ends the generator and sets `done: true`; further calls to `next()` return `{ done: true }`.