Get ALL methods/functions in a class/object

February 1, 2023

I need to be able to get all the functions of a class/object on multiple layers. I have only been able to find single-layered methods, but I know this is possible, as JSON.stringify removes every function from an object, so there must be a way to get every function from an object. How would I do this?

const getMethods = (obj) => {
  let properties = []
  let currentObj = obj
  do {
    Object.getOwnPropertyNames(currentObj).map(item => properties.push(item))
  } while ((currentObj = Object.getPrototypeOf(currentObj)));
  return [...properties].filter(item => typeof obj[item] === 'function')
}

var obj = {
  a: [],
  b: {
    e: null,
    f: function() {},
    g: {
      h: function() {},
    },
  },
  c: {
  },
  d: function() {},
}

console.log(getMethods(obj));

>Solution :

You can use Array#flatMap with recursion.

let obj = {
  a: [],
  b: {
    e: null,
    f: function f() {},
    g: {
      h: function h() {},
    },
  },
  c: {
  },
  d: function d() {},
}
function getFunctions(obj) {
  return Object.values(obj).flatMap(x => typeof x === 'function' ? x : 
    typeof x === 'object' && x ? getFunctions(x) : []);
}
console.log(getFunctions(obj));