TypeError: "x" is not a function

const x = document.getElementByID("foo");
// TypeError: document.getElementByID is not a function

const x = document.getElementById("foo");

const obj = { a: 13, b: 37, c: 42 };

obj.map((num) => num * 2);

// TypeError: obj.map is not a function

const numbers = [1, 4, 9];

numbers.map((num) => num * 2); // [2, 8, 18]

function Dog() {
  this.age = 11;
  this.color = "black";
  this.name = "Ralph";
  return this;
}

Dog.prototype.name = function (name) {
  this.name = name;
  return this;
};

const myNewDog = new Dog();
myNewDog.name("Cassidy"); // TypeError: myNewDog.name is not a function

function Dog() {
  this.age = 11;
  this.color = "black";
  this.dogName = "Ralph"; // Using this.dogName instead of .name
  return this;
}

Dog.prototype.name = function (name) {
  this.dogName = name;
  return this;
};

const myNewDog = new Dog();
myNewDog.name("Cassidy"); // Dog { age: 11, color: 'black', dogName: 'Cassidy' }

const sixteen = 2(3 + 5);
console.log(`2 x (3 + 5) is ${sixteen}`);
// Uncaught TypeError: 2 is not a function

const sixteen = 2 * (3 + 5);
console.log(`2 x (3 + 5)  ${sixteen}`);
// 2 x (3 + 5)  16

function helpers() {}

helpers.groupBy = function (objectArray, property) {
  return objectArray.reduce((acc, obj) => {
    const key = obj[property];
    acc[key] ??= [];
    acc[key].push(obj);
    return acc;
  }, {});
};

export default helpers;

import helpers from "./helpers";