JS TIP: R.isNil() checks null AND undefined

JS TIP: R.isNil() checks null AND undefined

⚠️ Be careful when replacing classic ===𝒏𝒖𝒍𝒍 with Ramda APi 𝑹.𝒊𝒔𝑵𝒊𝒍() because it could mislead ↩️ your business logic.

Imagine you declare an object but does not assign it.

𝒍𝒆𝒕 𝒎𝒚𝑶𝒓𝒅𝒆𝒓;

And later🕑 in the code you set it to null when there is an error❌:

onError(){
 myOrder=null
}

And somewhere🎯 in the code you check with ===𝐧𝐮𝐥𝐥, your order:

if(myOrder===null){
 dropOrder()
} else {
 //continue order processing
 myOrder = getOrderFromSomeService();
}

if you replace it with 𝑹.𝒊𝒔𝑵𝒊𝒍() of Ramda API, you will take the 𝒏𝒖𝒍𝒍  values AND the 𝒖𝒏𝒅𝒆𝒇𝒊𝒏𝒆𝒅 values.

Maybe you process the 𝒖𝒏𝒅𝒆𝒇𝒊𝒏𝒆𝒅 later in the business implementation, in such case, the 𝑹.𝒊𝒔𝑵𝒊𝒍() will mislead🔥 your intent.

if(R.isNil(myOrder)){
 dropOrder()
} else {
 // will never happen for undefined myOrder 🔥🔥🔥
 myOrder = getOrderFromSomeService();
}

#javascript #programming #nullcheck #ramda