The owner object is robot. this is the internal representation of the owner object, so it would make more sense to use it, rather than the name of the owner object. What happens if we clone this object under another name? It will still be referring to robot.
My code is ‘wrong’, in the second exercise it states:
Inside the robot object, add a method named provideInfo . Inside the body of provideInfo() , return the following string by using interpolation:
I am MODEL and my current energy level is ENERGYLEVEL.
Replace ‘MODEL’ and ‘ENERGYLEVEL’ with the calling object’s model and energyLevel property.
And my code is:
const robot = {
model: '1E78V2',
energyLevel: 100,
provideInfo() {
return `I am a ${this.model} and my current energy level is ${this.energyLevel}. `;
}
};
console.log(robot.provideInfo());
But it says I have an error. Not a code error, but apparently not the right way to do it. I even went as far as logging the result to the console, this is the output:
Output:
I am a 1E78V2 and my current energy level is 100.
I can’t find a clue on why this is wrong!
EDIT: My ignorance found out you have to put I am MODEL not I am a MODEL
I don’t understand what the point of the “this” keyword is. Can’t you just use the name of the object instead, which makes it more clear what you’re referring to?
What if the need arises to clone the object, dynamically. If we use ‘this’ in the methods, it operates in any context, not just the original object as it would if we didn’t use ‘this’.
Bottom line, ‘this’ takes on the execution context of the owner object, and having the ability to clone objects depends upon this encapsulation.
What did I do wrong? It is not letting me pass #2…
const robot = {
model : ‘1E78V2’,
energyLevel : 100,
provideInfo(){
return I am ${this.model} and my current energy level is ${this.energyLevel} .
}
};
robot.provideInfo();
That’s strange, why is dietType not defined even though it’s a property of goat ? That’s because inside the scope of the .diet() method, we don’t automatically have access to other properties of the goat object.
I did not understand why we don’t have automatic access to the other properties of the goat object and what does that mean ‘having automatic access’.
Hi;
I done the exercise. Even console.log printed me the correct answer. But I don’t understand the meaning of the error.
this is what I done:
const robot = {
model : ‘1E78V2’,
energyLevel : 100,
provideInfo(){
return I am MODEL ${this.model} and my current energy level is ENERGYLEVEL ${this.energyLevel}.
}
};
console.log(robot.provideInfo());// printed: I am MODEL 1E78V2 and my current energy level is ENERGYLEVEL 100.
But what is this error:
Did you return the string ‘I am MODEL and my current energy level is ENERGYLEVEL.’ and replaced MODEL and ENERGYLEVEL? Make sure you’re NOT logging the string, but returning it.
In the theory of this exercise that is presented to us, as a first example on where to use the ‘this’ keyword we are given the following syntax that will throw an error:
const goat = {
dietType: ‘herbivore’,
makeSound() {
console.log(‘baaa’);
},
diet() {
console.log(dietType);
}
};
goat.diet();
// Output will be “ReferenceError: dietType is not defined”
And we are told that we should use ‘this’ inside our diet() method:
diet() {
console.log(dietType);
}
But to me it seems the error is thrown because we are accessing an object property in a wrong way:
console.log(dietType);
instead of
console.log(goat.dietType);
So my question will be, why use ‘this’ instead of the object itself, like I mentioned above?
While maybe not practical, it is possible to change the name of an object just by assigning it to the new name, then delete the original reference.
ram = goat
delete goat
If we used goat.dietType then this would raise an error…
ram.diet()
As mentioned, this is not a very practical example, but it does show how important it is to write re-usable code so it is simpler to maintain and less prone to bugs. this fits that role, perfectly.
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