How can I ensure that an array of objects contains only one of a particular key with Joi?

Question

I have something like:

  let moduleId

  moduleRackOutputs.forEach((output) => {
    if (!moduleId) {
      moduleId = output.moduleId
    } else if (output.moduleId !== moduleId) {
      errors.add([
        'The drawing contains more than one module type. Multiple module types are not yet supported by the PVsyst RPA.'
      ])
    }
  })

I want to convert this to a Joi schema. How would I accomplish this?

Thank you

Answer 1

This can be accomplished as follows:

Joi.array()
    .items(
        Joi.object().keys({
            moduleId: Joi.string().required(),
            framingType: Joi.string().required()
        })
    )
    .unique((a, b) => a.moduleId !== b.moduleId)
    .message({
        'array.unique': 'The drawing contains more than one module type...'
    })
    .unique((a, b) => a.framingType !== b.framingType)
    .message({
        'array.unique': 'The drawing contains more than one framing type...'
    })