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

Composition

Functional composition is a technique or pattern that allows us to combine multiple functions to create a more complex function.

The following code snippet declares a function used to trim a string and a function used to transform a piece of text in uppercase text:

const trim = (s: string) => s.trim();
const capitalize = (s: string) => s.toUpperCase(); 

We can create a function that performs both the preceding operations by composing them:

    const trimAndCapitalize = (s: string) => capitalize(trim(s));

The variable trimAndCapitalize is a function that invokes the trim function using s as its argument and passes its return to the capitalize function. We can invoke the trimAndCapitalize function as follows:

trimAndCapitalize(" hello ...
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