json-server Converts Numeric "id" Fields to Strings

[RushiLee]

Steps-
1.Create a JSON file (Ninja.json) with the following content
{
"Ninjas": [
{
"UID": 1,
"name": "Neji",
"courses": ["Maths", "Science"],
"ContactNum": 1111,
"Location": "Mumbai"
},
{
"UID": 2,
"name": "RockLee",
"courses": ["Magic", "Science"],
"ContactNum": 2222,
"Location": "Goa"
},
{
"UID": 3,
"name": "Garaa",
"courses": ["Geo", "Science"],
"ContactNum": 2222,
"Location": "Goa"
}
]
}

2.Start json-server with
json-server Ninja.json

3.Perform a GET request to http://localhost:3000/Ninjas

Expected Behavior
{
"Ninjas": [
{
"id": 1,
"name": "Neji",
"courses": ["Maths", "Science"],
"ContactNum": 1111,
"Location": "Mumbai"
},
{
"id": 2,
"name": "RockLee",
"courses": ["Magic", "Science"],
"ContactNum": 2222,
"Location": "Goa"
},
{
"id": 3,
"name": "Garaa",
"courses": ["Geo", "Science"],
"ContactNum": 2222,
"Location": "Goa"
},
{
"id": 4,
"name": "Naruto",
"courses": ["Hindi", "Maths"],
"ContactNum": 2222,
"Location": "Goa"
},
{
"id": 5,
"name": "Sasuke",
"courses": ["History", "Economics"],
"ContactNum": 2222,
"Location": "Goa"
}
]
}

Actual Behavior
[
{
"id": "1",
"name": "Neji",
"courses": [
"Maths",
"Science"
],
"ContactNum": 1111,
"Location": "Mumbai"
},
{
"id": "2",
"name": "RockLee",
"courses": [
"Magic",
"Science"
],
"ContactNum": 2222,
"Location": "Goa"
},
{
"id": "3",
"name": "Garaa",
"courses": [
"Geo",
"Science"
],
"ContactNum": 2222,
"Location": "Goa"
},
{
"id": "4",
"name": "Naruto",
"courses": [
"Hindi",
"Maths"
],
"ContactNum": 2222,
"Location": "Goa"
},
{
"id": "5",
"name": "Sasuke",
"courses": [
"History",
"Economics"
],
"ContactNum": 2222,
"Location": "Goa"
}
]

Workaround:
Changing id to a different field name (e.g., uid) prevents this behavior

Additional Details-
C:\Windows\System32>npm --version
10.9.2

C:\Windows\System32>node --version
v22.14.0

[qx-7]

I am having a similar problem on Ubuntu via WSL.

The Issue

Only fields called id are affected. The following:

{
  "foo": [ 
    { "test": 1, "id": 1 },
    { "test": 2, "id": 2 }
  ]
}

will be served as:

[
  {
    "test": 1,
    "id": "1"
  },
  {
    "test": 2,
    "id": "2"
  }
]

Workaround

However, the broken behavior stops if I save the file while the server is watching it, even if nothing in the file changed. Using touch db.json also caused the broken behavior to stop while the server is running.

Hopefully this helps others! I'm having a lot of fun with the tool so far :)