javascript - Copy properties of object to another skipping undefined ones

Question

How can I copy a list of properties from a object to another skipping the null or undefined values?

Something like this

const obj1 = { prop1: 'value', prop2: undefined }

const obj2 = copy(obj1, ['prop1', 'prop2', 'prop3']) // prop3 doesn't exist and prop2 should be excluded

console.log(obj2) // should print { prop1: 'value' }

question from:https://stackoverflow.com/questions/65943495/copy-properties-of-object-to-another-skipping-undefined-ones

Answer 1

Try this:

const obj1 = { prop1: 'value', prop2: undefined }

function copy(obj1, props)
{
  return props.reduce(
    (acum, current) => 
      (obj1[current] !== undefined && obj1[current] !== null) ? 
        ({...acum, [current]:obj1[current]}):
        acum
    ,{}
  )
}

const obj2 = copy(obj1, ['prop1', 'prop2', 'prop3']) // prop3 doesn't exist and prop2 should be excluded

console.log(obj2) // should print { prop1: 'value' }