Jest testing, keeps return undefined?-CodePudding

I'm trying to test a function with jest, and I simply can figure out what's wrong? It keeps saying it expects to return the output, but got undefined. I have tested the function elsewhere where it seems to return the correct array.

I'm calling my my function and passing it an Object, it's then supposed to return an array. Then I'm calling .toEqual(output) which is an array.

//This is my function
const allAddresses = [
];

const updateAllAddresses = (obj) => {
  const transferAmount = obj.transferAmount;
  const to = obj.to;
  const transferAddress = obj.address;
  const newBalance = obj.newBalance;
  const addressArr = [...allAddresses];
  console.log("This addressArr", addressArr);
  console.log("this is obj", obj);
  //To set your account to the new balance after transfer and
  //to check if the address you transfer to is your own account
  addressArr.map((address) => {
    if (address.account === transferAddress) {
      console.log("This is inside the map !!!!");
      address.balance = Number(newBalance);
    }
    if (address.account === to) {
      console.log("2");
      address.balance = Number(transferAmount)   Number(address.balance);
    }
    console.log("last part of the testing", addressArr);
    return addressArr;
  });
};

const obj = {
};
const output = [
];


//This is my test
describe("Update array", () => {
  test("update the array with the new information", () => {
    expect(updateAllAddresses(obj)).toEqual(output);
  });
});

CodePudding user response：

You cannot short circuit and return inside a map function. You should return the object after the map

Also, when you change address inside the map; It really does not change anything, since that address variable will be removed from memory on next iteration

CodePudding user response：

There is a problem with your updateAllAddresses method. You are not returning anything then the result of your function becomes undefined;

add return to where you are using .map method.

  return addressArr.map((address) => {
    if (address.account === transferAddress) {
      console.log("This is inside the map !!!!");
      address.balance = Number(newBalance);
    }
    if (address.account === to) {
      console.log("2");
      address.balance = Number(transferAmount)   Number(address.balance);
     }
    console.log("last part of the testing", addressArr);
    return address;
  });