JavaScript Possible Iteration Over Unexpected
The IDE is recommending that you add a test:
if (awards.hasOwnProperty(i)) {
...
}
inside the for
loop.
I personally recommend not doing this, and disabling the warning if possible. There's simply no need in most code, and even less need in ES5 code where you can safely add non-enumerable properties to an object using Object.defineProperty
The hasOwnProperty
check is only necessary if you have unsafely added new (enumerable) properties to Object.prototype
, so the simplest fix is don't do that.
jQuery doesn't perform this test - they explicitly document that jQuery will break if Object.prototype
is unsafely modified.
You can also refactor your loop into:
const keys = Object.keys(object);
for (const key of keys){
// do something with object[key];
}
Every object in javascript has prototype which has its own properties(native/inherited methods/properties) and properties which are directly attached to object itself.
When you iterate over an object, it will iterate the properties of the object itself and the properties of the prototype of the object.
So, In order to avoid iterating over the prototype, it is recommended to use hasOwnProperty method which return true only when the object has the mentioned property directly. i.e, Not inside prototype
Example
for (var k in object) {
if (object.hasOwnProperty(k)) {
// do your computation here.
}
}
More details can be found here