React Design Patterns and Best Practices - Second Edition

Composition

Finally, an important concept in FP that can be applied to React is composition. Functions (and components) can be combined to produce new functions with more advanced features and properties.

Consider the following functions:

const add = (x, y) => x + y; const square = x => x * x;

These functions can be composed together to create a new function that adds two numbers and then doubles the result:

const addAndSquare = (x, y) => square(add(x, y));

Following this paradigm, we end up with small, simple, testable pure functions that can be composed together.