4-methods.js

'use strict';

const methods = iface => {
   // Introspect all properties of iface object and
  // extract function names and number of arguments
  // For example: {
  //   m1: x => [x],
  //   m2: function (x, y) {
  //     return [x, y];
  //   },
  //   m3(x, y, z) {
  //     return [x, y, z];
  //   }
  // will return: [
  //   ['m1', 1],
  //   ['m2', 2],
  //   ['m3', 3]
  // ]
  const methodNames = Object.keys(iface);
  const methodsArray = methodNames.reduce((acc, methodName) => {
    const prop = iface[methodName];
    if (typeof prop === 'function') { 
      acc.push([methodName, prop.length]); 
    }
    return acc;
  }, []);

  return methodsArray;
};

module.exports = { methods };