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Strange variable initialization in Eloquent JavaScript

I started reading the section on Node.js in the online copy of Eloquent JavaScript (BTW, a well-done book). All examples use the following construct to capture the result of a require() call:

const {fs} = require("fs");

If I try to reproduce this in my node.js 8.9.3 64 bits, the resulting fs variable is undefined. A more usual construct:

const fs = require("fs");

instead returns a usable variable.

My question. I'm missing something obvious? (Maybe I simply have to read the book from the beginning...). Which benefits the first construct gives instead of the more normal variable definition? Thanks!

Solution

  • In ES6, you can destruct objects like this:

    const obj = {first: 1, second: 2};
const {first, second} = obj;

console.log(first,second); // 1 2

    Similarly, Node's fs has a member readFile that is being used like:

    const {readFile} = require('fs');