matchedData does not include nullable optionals

[AndrewBarba]

Describe the bug

There's currently no easy way to allow a property to be set to null, and exclude any data that was not validated. A common pattern for us is to sanitize the request body post-validation using the matchedData function, for example:

// POST /user { username: "Andrew", age: null }

await validate(req, [
  body("username").isString(), 
  body("age").optional({ nullable: true }).isInt(),
  body("name").optional().isString()
])

req.body = matchedData(req, { locations: 'body' })

assert(req.body.age === null) // fails

I know matchedData provides the includeOptionals option but this option will take all optionals and then set them to undefined, which is definitely not what we want.

As is - there is no way to get access to just the nullable properties which I consider a bug in matchedData as it did in fact match against a null property and validated it according to optional({ nullable: true })

Expected behavior

assert(req.body.age === null) // succeeds

Current behavior

assert(req.body.age === null) // fails

Express-validator version:

• Version: 6.x

[herbertpimentel]

+1 I agree, a nullable value should be inclueded in the matchedData, by definition, the rule says it can be null, and if it is null. it matches the definitions

[mrollinsiv]

Is there any update on this issue?

[erikhh92]

Yup, waiting here too. The problem is with this kind of types:

interface Body { age: number | null }

If i want to update a item that now has a value of age: 5 and make it null, i can't do this because the data come filtered without the null value, so the update item remains the same.