Skip to Content
Learning TypeScript 2.x - Second Edition
book

Learning TypeScript 2.x - Second Edition

by Remo H. Jansen
April 2018
Beginner content levelBeginner
536 pages
13h 21m
English
Packt Publishing
Content preview from Learning TypeScript 2.x - Second Edition

Closures

Closures are one of the most powerful features available at runtime, but they are also one of the most misunderstood. The Mozilla developer network defines closures as follows:

"Closures are functions that refer to independent (free) variables. In other words, the function defined in the closure 'remembers' the environment in which it was created".

We understand independent (free) variables as variables that persist beyond the lexical scope from which they were created. Let's look at an example:

function makeArmy() { 
    const shooters = []; 
    for (let i = 0; i < 10; i++) { 
        const shooter = () => { // a shooter is a function 
            console.log(i); // which should display it's number 
        }; 
        shooters.push(shooter); 
    } 
    return shooters; 
} 
The preceding ...
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,
and much more.
Start your free trial

You might also like

Mastering TypeScript - Fourth Edition

Mastering TypeScript - Fourth Edition

Nathan Rozentals
Learning TypeScript

Learning TypeScript

Josh Goldberg
TypeScript for Beginners

TypeScript for Beginners

Bharath Thippireddy

Publisher Resources

ISBN: 9781788391474Supplemental Content