Hi, I am encountering a strange problem. I don’t understand what the the exercise is asking me to do. Should I just look at the answer? Link to the module- [image] freeCodeCamp.org Learn to Code — For Free Thanks,

You need to create a new prototype function of Array that acts like this: [image] Array.prototype.map() - JavaScript | MDN The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

But we can’t use the map function.

The challenge wants you to add a custom function to the Prototype with the same functionality that Array.map does i.e. loop through each elements and and apply the provided callback function and push to new array , and return the array with newly calculated elements.

Try logging this and see what’s the value of it.

when I try to log this value is undefined. console.log(this).

Log it inside the function, and try to not look at the solutions, you are hindering your learning and progress

@deetigupta8 this in Javascript w3schools has a nice introduction about this keyword in JS. It’s a good starting point for understanding this .

Thanks!! @saurabhv749 :star2: :star2:

You are right. But sometimes I don’t know what else to do :frowning: I will try more. Thank you for getting back :star2: :star2:

Implement map on a Prototype | Functional Programming

Curriculum Help

deetigupta8 July 1, 2022, 9:18am 5

All too confusing. I had to look at the solution because I was lost on ideas how to approach the problem. In the first solution why do we have this.length? shouldn’t it be callback.length?
Please guide

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Implement map on a Prototype | Functional Programming

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