ljharb/qs

Stringify with "arrayFormat: comma" encodes objects inside arrays as "[object Object]"

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#378 opened on Aug 11, 2020

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 (30 comments) (6 reactions) (0 assignees)JavaScript (8,015 stars) (744 forks)batch import
bughelp wantedstringify

Description

Tested on version 6.9.4

Stringify with arrayFormat: comma encodes objects inside arrays as [object Object]

I took this code from the examples:

qs.stringify({ a: { b: { c: 'd', e: 'f' } } });
// 'a[b][c]=d&a[b][e]=f'

and added an array around the inside object

qs.stringify({ a: { b: [{ c: 'd', e: 'f' }] } }, { encode: false, arrayFormat: 'comma' })
// 'a[b]=[object Object]'

The inside data is lost this way.

I tried the allowDots setting too, but that didn't fix anything.

I'm not sure what the output should be like exactly, but this is unusable right now. In my project I did Array.map(p => ${p.ID}::${p.Value}), but that's very specific and I'm unsure if the :: is a good seperator.

Contributor guide

Tech stack
javascript
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
needs maintainer response
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
JavaScriptquery string encodingqs library API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
Investigate the stringify function's handling of arrayFormat: 'comma' in the source code. Determine the expected behavior for nested objects inside arrays under this format. Review the discussion in the issue comments (e.g., maintainer's stance) and consider both preserving object structure or opting for a consistent string representation. Possibly propose a new option or fix to properly serialize objects as a string representation like JSON or a custom format.