How "anyOf" is working?

[SkeLLLa]

Hi. I can see that this lib supports anyOf. But according to description it looks like it acts like oneOf.
For example in ajv anyOf should match 1 or more and oneOf should match exactly one.

Also it seems working correctly if anyOf items differ by type. However if they not, it will fail and just take the last object to validate.

Under the hood it converts anyOf to if-else clause with ajv.validate. But ajv supports oneOf and allOf. Why it just not pass the whole parent object (that has oneOf or anyOf) directly to ajv?

test('object with multiple objects', (t) => {
  t.plan(2)

  const schema = {
    title: 'object with multiple objects',
    type: 'object',
    properties: {
      prop: {
        anyOf: [{
          type: 'object',
          properties: {
            str: {
              type: 'string'
            },
            str1: {
              type: 'string'
            }
          }
        },{
          type: 'object',
          properties: {
            str: {
              type: 'string'
            }
          }
        }, {
          type: 'object',
          properties: {
            str1: {
              type: 'string'
            }
          }
        }]
      }
    }
  }
  const stringify = build(schema)

  try {
    const value = stringify({
      prop: {str: 'string', str1: 'string1'}
    })
    t.is(value, '{"prop":{"str":"string", "str1":"string1"}}')
  } catch (e) {
    t.fail()
  }
})

    +++ found
    --- wanted
    -{"prop":{"str":"string", "str1":"string1"}}
    +{"prop":{"str1":"string1"}}

I've tried to make a fix for that, but seems I'm missing something and if I add the code it throws ajv is not defined exception during tests.

[mcollina]

You would need to update https://github.com/fastify/fast-json-stringify/blob/master/index.js#L106-L118 to traverse the full tree.

[mcollina]

Is this still a problem? This might be fixed in #112.

[SkeLLLa]

@mcollina Unfortunately I don't know exactly. I'm using Object.assing and then registering schema instead of anyOf. But you may easily check it with the test case I've provided in the first message.