January 2020
Intermediate to advanced
470 pages
11h 13m
English
Content preview from Mastering JavaScript Functional Programming - Second Edition
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Extracting data from objects
Let's start with a simple example. Suppose that we have some geographic data (as shown in the following snippet) related to some South American countries and the coordinates (latitude and longitude) of their capitals. Let's say that we want to calculate the average position of those cities. (No, I don't have a clue why we'd want to do that.) How would we go about it?
const markers = [ {name: "AR", lat: -34.6, lon: -58.4}, {name: "BO", lat: -16.5, lon: -68.1}, {name: "BR", lat: -15.8, lon: -47.9}, {name: "CL", lat: -33.4, lon: -70.7}, {name: "CO", lat: 4.6, lon: -74.0}, {name: "EC", lat: -0.3, lon: -78.6}, {name: "PE", lat: -12.0, lon: -77.0}, {name: "PY", lat: -25.2, lon: -57.5}, {name: "UY", lat: -34.9, lon: ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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