Hands-On Design Patterns with React Native

Examples of higher-order functions

There are a number of functions that are higher-order functions and you use them on a daily basis:

• Array.prototype.map:

someArray.map(function callback(currentValue, index, array){    // Return new element});// or in the shorter formsomeArray.map((currentValue, index, array) => { //... });

• Array.prototype.filter:

someArray.filter(function callback(currentValue, index, array){    // Returns true or false});// or in the shorter formsomeArray.filter((currentValue, index, array) => { //... });

• Array.prototype.reduce:

someArray.reduce(    function callback(previousValue, currentValue, index, array){        // Returns whatever    },    initialValue);// or in the shorter formsomeArray.reduce((previousValue, currentValue, index, ...