JSFiddle - React, Tailwind, and code Playground

by Jessie Lau

JavaScript

class Underscore:

    def map(self, lst, callback):
        new_lst = []
        for i in lst:
            new_lst.push(callback(i))
        return new_lst

    def reduce(self, lst, callback):
        total = 0
            for i in lst:
                total += callback(i)
        return total
        # your code here

    def find(self, lst, callback):
        # your code here

    def filter(self, lst, callback):
        # your code

    def reject(self, lst, callback):
        # your code


# you just created a library with 5 methods!
# let's create an instance of our class
_ = Underscore() # yes we are setting our instance to a variable that
# is an underscore
evens = _.filter([1, 2, 3, 4, 5, 6], lambda x: x % 2 == 0)
# should return [2, 4, 6] after you finish implementing the code above