Accessing object properties with bracket notation
In JavaScript, we can use bracket notation to access an object’s property whose name is stored in a variable.
const storage = {
candy: 5,
chocolate: 6
}
// We can access properties directly by name using dot-notation. We can also
// access them by writing their name as a string in square brackets:
storage.candy // ⇒ 5
storage['candy'] // ⇒ 5
// If we don’t know the name of the property because it only exists in a
// variable, we _have_ to use bracket notation:
const lookUp = 'chocolate'
storage.lookUp // ⇒ undefined (looks for missing property 'lookUp')
storage[lookUp] // ⇒ 6