Combining multiple conditions into one in Javascript

Question

How can i shorten this code? I want to return all values except "abc" or "xyz" or "pqr"

return this.value != "abc" && this.value != "xyz"  && this.value != "pqr";

Answer 1

You can use an array:

return ["abc","xyz","pqr"].indexOf(this.value) == -1;

Or an object:

return !({"abc":1,"xyz":1,"pqr":1}).hasOwnProperty(this.value);

Answer 2

2 most common ways are:

1. regex

   /^(abc|xyz|pqr)$/.test(this.value)

2. object property lookup

   this.value in ({'abc':1,'xyz':1,'pqr':1})

Note that regex-based solution (#1) will most definitely be slower than plain comparison (your version) or property lookup (#2).

Also, remember that property lookup is not very reliable, as it might report false positives for any key that's named the same as any of Object.prototype.* properties (e.g. "toString", "valueOf", etc.)

Answer 3

May I ask why you want it shortened? Like others have pointed out you probably can't gain much performancewise, and what you have is pretty readable.