Shorten JS if or statement [duplicate]

Answer 1

You could write a function:

function isAny(x) {
  for (var i = 1; i < arguments.length; ++i)
    if (arguments[i] === x) return true;
  return false;
}

Then you can say:

if (isAny(x, 1, 2, 3, 4)) { /* ... */ }

(Whether to use "===" or "==" would depend on the exact semantics you want.)