Add ability to ignore extraneous properties, instead of failing with error

[ronniel1]

Hi,

I'm evaluating this package for replacing Joi validations that we have.
The main thing I like in this package is that I don't need to declare the object type and schema separately (using t.InferType).

One thing that I'm missing is the ability to to ignore extraneous properties from the returned value of t.as(). So if I get invalid properties, there will be no error, and the object returned from t.as() will not include these properties

[arcanis]

Can you share a full example of what you have and what you expect?

[ronniel1]

Here is an example:

   const isData = t.isObject({
      data1: t.isOptional(t.isString()),
      data2: t.isString(),
   });

   const dynamicData = {
      data1: 'd1',
      data2: 'd2',
      data3: 'd2',
   };

   const convertedData = t.as(dynamicData, isData, { errors: true });
   console.log(convertedData.errors);
   console.log(convertedData.value);

Expected result is not error, and value to containt:

{
   data1: 'd1',
   data2: 'd2',
}

[whorvath2]

This is a darn good idea fwiw - There are times I've found it more valuable to drop or ignore extra data rather than reject a call to an endpoint or method. HOWEVER, I'd be curious to know if there are security implications to this with client-supplied objects. Could the data I'm completely ignoring somehow end up stuck in memory somewhere and inject malicious instructions, or does the runtime environment clean it up for me?