Higher Order Functions

In plain terms

What you need to know

• •Take or return functions
• •map, filter, reduce
• •Composition

Try it yourself

Copy the code below and run it in your browser console or a code editor:

const numbers = [1, 2, 3, 4];
numbers.map(x => x * 2);     // [2, 4, 6, 8]
numbers.filter(x => x > 2);  // [3, 4]
numbers.reduce((a, b) => a + b, 0);  // 10

function withLogging(fn) {
  return (...args) => {
    console.log('Calling with', args);
    return fn(...args);
  };
}

Learn more

Dive deeper with these trusted resources: