javascript/typescript object null check

Question

Is there a difference in performance while doing null checks in below 2 ways -

if (!someObject) {
   // dosomething
}

vs

if (someObject != null) {
   // dosomething
}

Answer 1

!someObject checks for all falsy values.

Not ( empty string, undefined, null, 0, false) - will all pass the condition

where as the first condition only checks for null.

 if (someObject !== null) {
    console.log('falsey');
 }

 someObject = null;      // no message in console
 someObject = '';        // falsey
 someObject = undefined; // falsey
 someObject = 0;         // falsey
 someObject = false;     // falsey

Falsey check

if (!someObject) {
    console.log('falsey');
 }

 someObject = null;      // no message in console
 someObject = '';        // no message in console
 someObject = undefined; // no message in console
 someObject = 0;         // no message in console
 someObject = false;     // no message in console