mk-etlinger/javascript-map-lab-v-000

JavaScript Map Lab

Overview

The .map() function allows us to transform elements in an array from one value to another, we can take a look at some practical examples. There's no need to implement your own map() function, since we can readily use the Array.prototype.map() method.

Uncovering alliances

Imagine we're a top-end cyber researcher for DARPA. The military has given us a list of robots. We also have a manifest of all known Decepticon robot names. Our job is to go through the list of robots, and set their alliance accordingly.

• Create a new variable called sortedRobots;
• The value of this variable is the mapped robots array;
• Return each robot object with the alliance filled in with either an 'autobot' or 'decepticon' string.
• To figure out a robot's alliance, check if their name exists in the knownDecepticons array.
• (Hint: use Array.prototype.includes to easily check if an element exists in an array.)
• The original objects in the robots array must not be modified, so be sure to use Object.assign()

The White Stripes

A zebra without stripes is just a silly looking horse. We have a zebraStripes array that represents the stripes of our dancing friend up here, but the stripes don't have any color yet. Let's fix that!

• Create a new variable called coloredZebraStripes;
• The value of this variable is the mapped zebraStripes array;
• Return each stripe object with the stripe filled in with either a 'black' or 'white' string.
• A stripe is black when the stripe's index is even, and it's white if a stripe's index is odd.
• (Hint: the callback we pass to .map() takes more than one parameter)
• The original objects in the zebraStripes array must not be modified, so be sure to use Object.assign()

Resources

• MDN: Array.prototype.map()

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