What causes an error when trying to access with the member access operator?

Question

What causes an error when trying to access with the member access operator?

When dealing with object properties in the code snippet below, an error is thrown when trying to access the object using the Member Access. Why does this happen?

 var d = {a: 10, b: 20, c:30};
         
         var keys = Object.getOwnPropertyNames(d);
         
         for(let i = 0; i < keys.length; i++){
            console.log(d[keys[i]]);
            //console.log(d.keys[i]); //throws error
         }

In the given example, one possible explanation behind this issue could be that if we attempt to access it with the member access operator, it would directly try to access d without properly initializing keys[i]. Is this hypothesis accurate?

javascript

Answer 1

Answer №1

Initially, an attempt is made to access and retrieve the item at index i from d.keys. Let's see what happens if there exists an item with the name keys inside d:

var d = {
  a: 10,
  b: 20,
  c: 30,
  keys: [1, 2, 3, 4]
};

var keys = Object.getOwnPropertyNames(d);

for (let i = 0; i < keys.length; i++) {
  // console.log(d[keys[i]]);
  console.log(d.keys[i]); //this will work if it finds any property named keys
}

Answer 2

Initially, an attempt is made to access and retrieve the item at index i from d.keys. Let's see what happens if there exists an item with the name keys inside d:

var d = {
  a: 10,
  b: 20,
  c: 30,
  keys: [1, 2, 3, 4]
};

var keys = Object.getOwnPropertyNames(d);

for (let i = 0; i < keys.length; i++) {
  // console.log(d[keys[i]]);
  console.log(d.keys[i]); //this will work if it finds any property named keys
}

What causes an error when trying to access with the member access operator?

Answer №1

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