IncomingForm end event emitted twice (at least)

[dresende]

Support plan

• Which support plan is this issue covered by? Community
• Currently blocking your project/work? no
• Affecting a production system? yes

Context

• Node.js version: v14 and v16 at least
• Release Line of Formidable: Current
• Formidable exact version: 2.0.1 (npm)
• Environment: node, macOS and Linux, does not matter
• Used with (popular names of modules): express

What are you trying to achieve or the steps to reproduce?

let form = new formidable.IncomingForm();

form.on("field", (field, value) => {
    console.log("field", field, value);
});

form.on("end", () => {
    console.log("end");
});

What was the result you got?

Printed "end" twice.

What result did you expect?

Print "end" once. I tested with a simple Postman form with 2 fields.

I bypassed the error using form.once("end") but this doesn't feel right.

[GrosSacASac]

I 'll have a look

[tunnckoCore]

Interesting.

@dresende when 3 fields, does it emit 3 times? Try mixing fields types too: 3 fields and 1 file - emit 3-4 times?

Should add test in test/unit/formidable.test.js to check it's emitted once. Also all the cases.

Hm.

[dresende]

No, it seems to just emit 2 events, no matter if I have 2 or 3 fields. I was using multipart for form-data (fields and files) but had no files. But since I had no files I also tested with x-www-form-urlencoded and same thing happens.

I might have hit a very very specific case, or not.. I use formidable for years now but I updated recently from 1.2.2 to 2.0.1. I made the necessary changes and I use it for a lot of forms on my app, only this one seems to have some kind of glitch.

[dresende]

Just tested with only 1 field and it still emits 2 events. And... this only occurs for form-data body type.

[tunnckoCore]

Thanks for testing.

Hm, yea.. definitely strange. We should look and follow the whole flow more carefully .

[LatenC]

Same issue happened with me also.
I am also using the same version - 2.0.1

[Fedacc]

I see the same issue also on version 2.0.0, event 'end' is emitted twice regardless of the number of files/fields received

[GrosSacASac]

Published as 3.2.3

[marcorocci]

the problem is in this part
form.on("end", () => { console.log("end"); });

should be
form.once("end", () => { console.log("end"); });

so once instead of on

[GrosSacASac]

@marcorocci true but the library should also not emit end twice to begin with

[dresende]

so once instead of on

That's obvious and that's how people worked around it until it is/was fixed.

[wbt]

That's obvious

Just about nothing is "obvious" to everybody. The original comment was intended to be helpful and could have been to folks who hadn't encountered that idea yet; no need to be dismissive.

[dresende]

Just about nothing is "obvious" to everybody.

That's obvious or a paradox? 😂

[julientype]

once done <<<< yes that ok as API ..... end is used for like body parts then flags the next part ....
Like end flags 2 times its probably socket or phrasing next part but has nothing...