Object does not equal to true or false

Question

So my uploaded media file (event.target.files[0]) does not equal to true or false. It has a typeof object.

It's part of some form state and I'd like to check the object whether all fields are not empty "".

I thought a JS object should always === true, but maybe this is different for 'files' objects?

Can you show your code so this can be narrowed down by the community? — GetSet, Jul 11 '20 at 15:26
An object won’t strictly equal true; an object is truthy, but that’s not what strict-equal checks for. — Dave Newton, Jul 11 '20 at 15:31

score 1 · Answer 1 · answered Jul 11 '20 at 15:34

1

=== tests for equal value and equal type (ref). typeof(true) is boolean but a file is not a boolean. So the comparison will never yield true.

answered Jul 11 '20 at 15:34

Daemon Beast · Accepted Answer · 2020-07-11T16:15:59.150

=== checks for strict equality, so the two values must be exactly the same.

An object is truthy, but does not equal true, so what you are really doing is { ... } === true, which is false.

If you want to check if none of the object's values are empty, you can filter for empty values:

const empty = Object.keys(theObject).length === 0 || Object.values(theObject).filter(value => {
  return value.trim() === '';
}).length > 0;

score -1 · Answer 3 · answered Jul 11 '20 at 15:41

-1

To check the type of a value, you must write

if( (typeof <your value>) == ("<expected type>")){
   ...
}

For example, a statement like this:

if( (typeof 42)=="number" )

is true.

answered Jul 11 '20 at 15:41

LoukasPap

This isn't idiomatic, an `if (o)` would be more than sufficient here. – Evan Trimboli Jul 11 '20 at 15:50

3 Answers3