Question

I have a little issue regarding IN operator in javascript.

As we know that simplifies redundant logical ORs.

I have the following statement:

if(value==="abc" || value==="cde" || value==="efg" || ...){
 ...
}

I could use

if(value in { "abc":1, "cde":1, "efg":1, ... }){
  ...
}

I wrote this as an example but Google Chrome Console get an error:

Uncaught SyntaxError: Unexpected token : 

Where’s my mistake?

Answer 1

To avoid bugs in case somewhere in your app Object.prototype has been modified, you should use:

if(({ "abc":1, "cde":1, "efg":1, ... }).hasOwnProperty(value)){
  ...
}