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Day 7 of 100DaysOfCode

Arttu Pyykönen
Engineering student. Trying to better myself everyday. I believe the best way to learn is by teaching.
・2 min read

Today was a great learning day! Worked on some more JavaScript with both the Eloquent JavaScript book and FreeCodeCamp. Time went super quickly!

Higher-order functions were quite difficult for me to grasp and took some time but at least it felt like I was learning!

Have a great day and good luck with your challenges, whether it be in the form of code or other aspects of life.

What I did today:

1. Read the rest of Chapter 5 of Eloquent JavaScript book

What I learned from it:

  • Using higher-order functions
  • Array methods: filter, map, reduce, some
  • Introduction to Composability

2. Did the exercises of Chapter 5 of Eloquent JavaScript

What I learned from it:

  • Higher-order functions are super tricky for me to grasp
  • Got some great problem-solving experience

3. Worked on the Basic JavaScript lessons at FreeCodeCamp

What I learned from it:

  • Working with objects
  • Manipulating and creating complex objects

Time spent learning:

Task 'reading_EJS'. Elapsed time: 59 min 34 s
Task 'ESJ_exercises'. Elapsed time: 96 min 48 s
Task 'FCC'. Elapsed time: 22 min 7 s

Time spent actually coding: 2h 14 min

Total time: 2h 58min 29s

Tracked by using my TaskTimer script and the WakaTime app

Further reading

Summary of Chapter 5 - Higher-Order functions

"Being able to pass function values to other functions is a deeply useful aspect of JavaScript. It allows us to write functions that model computations with “gaps” in them. The code that calls these functions can fill in the gaps by providing function values.

Arrays provide a number of useful higher-order methods. You can use forEach to loop over the elements in an array. The filter method returns a new array containing only the elements that pass the predicate function. Transforming an array by putting each element through a function is done with map. You can use reduce to combine all the elements in an array into a single value. The some method tests whether any element matches a given predicate function. And findIndex finds the position of the first element that matches a predicate." link


Check out FCC for best interactive exercises!


You can check my answers to the exercises of Eloquent JavaScript. You'll find them here.

That's it. See you all tomorrow!

Discussion (7)

pablohs1986 profile image
Pablo Herrero

Congrats and a question: in 100DaysOfCode you can do courses and exercises ??? I thought that you could only work on projects and that courses / exercises did not count. I'm asking you because I was thinking of starting the challenge.

miclgael profile image
Michael Gale

End of the day, 100DOC is open source. Fork the repo and do what you want. ;)

arttupyykonen profile image
Arttu Pyykönen Author

Yeah, I don't think it really matters what you do, as longs as you do something. You can read more at

miclgael profile image
Michael Gale

Arttu, awesome work 👏👏

I love Eloquent JavaScript. I have edition 5, so some of the stuff you did here is missing. I Might need to study up!

arttupyykonen profile image
Arttu Pyykönen Author

Check out the website! It's an awesome learning resource! Here's the link:

mpfdev profile image

Huge accomplishment! Congrats!

arttupyykonen profile image
Arttu Pyykönen Author