clojure style threading macro example in js

threading.js

// Threading macros, also known as arrow macros, 
// convert nested function calls into a linear flow of function calls, 
// improving readability. The idea is similar to 'pipelining'

const double = str => `${str} ${str}`;
const reverse = str => str.split("").reverse().join('');
const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1);
const pad = (maxLength, chr = ' ') => str => str.toString().padEnd(maxLength, chr);

const thread = function thread(...args) {
    return args.reduce((val, fn) => fn(val), this);
}
// Option A: Binding it to the Object constructor
Object.prototype['->'] = thread;

// Option B: creating a more 'clojuresque' variation
globalThis['->'] = (value, ...args) => thread.apply(value, args);

// EXAMPLE USAGE 
const str = 'carrot';

// Option A:
str['->'](capitalize, 
          reverse, 
          double,
          pad(20, 'Q')); //"torraCQQQQQQQQQQQQQQ torraCQQQQQQQQQQQQQQ"

// Option B:
globalThis['->'](str,
                 capitalize, 
                 reverse, 
                 double,
                 pad(20, 'Q')); //"torraCQQQQQQQQQQQQQQ torraCQQQQQQQQQQQQQQ"