How to check if an object contains a null value?

Question

I have an object:

let myObject = {first: "", second: null};

And I have a function:

return Object.values(myObject).some(
   objectValue => objectValue !== "" && typeof objectValue !== "undefined" && typeof objectValue !== null
);

What this does is that it returns true if an object has a set value and returns false if an object doesn't have any set values. The thing is that when I pass a null value, this function returns true (as if the object has a set value).

On other occasions it works fine. What is wrong here?

Your check is incorrect: typeof null is "object", not "null". stackoverflow.com/questions/18808226/why-is-typeof-null-object. Compare with null literal instead. — justinas
– justinas, Commented Jun 3, 2019 at 13:42

Bellash · Accepted Answer · 2019-06-03 14:04:34Z

1

null and undefined are falsy so you can only write this

return Object.values(myObject).some(
  objectValue => objectValue?true:false;
 );

null will return false in this case.

answered Jun 3, 2019 at 14:04

Bellash

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2 Comments

user47589 Over a year ago

You can simplify this and eliminate the ternary expression: !!objectValue

marsibarsi Over a year ago

it would be better to compare this way: objectValue === null, because objectValue will be as false for every falsy value like 0, NaN etc.

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