Function will not return an integer when multiplying two variables with numerical values (JS)-CodePudding

I am having issues getting my function to return product of two variables with numerical values.

The directions are: You want to write a function that takes in the name of a stock as a string and returns for you the total amount of money you have invested in that stock. e.g. if your function is given ‘AMZN’ it should return 4000.

This is my function, I keep returning NaN when I should be returning 4000.

let investments = [
  {stock: "AMZN", price: 400, numOfShares: 10},
  {stock: "AAPL", price: 300, numOfShares: 5},
  {stock: "BIDU", price: 250, numOfShares: 4}
  ];

calculateInvestedAmt = (stock) => {
  const totalAmt = investments.price * investments.numOfShares;
  return totalAmt; 
};

calculateInvestedAmt("AMZN");

CodePudding user response：

You have to use find method

const getStockPrice = (name) => {
    const stock = investments.find(s => s.stock === name);

    if (!stock) return undefined; // can't find stock

    returb stock.price * stock.numOfShares;
}

CodePudding user response：

investments.price and investments.numOfShares is undefined. That's why it is producing NaN, because you are multiplying two undefined values. You should first iterate over investments to find the stock you want.

CodePudding user response：

let investments = [
  {stock: "AMZN", price: 400, numOfShares: 10},
  {stock: "AMZN", price: 400, numOfShares: 10},
  {stock: "AAPL", price: 300, numOfShares: 5},
  {stock: "BIDU", price: 250, numOfShares: 4}
  ];

calculateInvestedAmt = (stockName) => {

  var totalAmt;
  
  var investedItem = investments.filter(invst => invst.stock === stockName);
  
  investedItem.map(item => { 
     totalAmt = item.price * item.numOfShares;
  });
  return totalAmt;
  
};

console.log(calculateInvestedAmt("AMZN"));