How I can start Iteration from 1 Using Object.entries() method JavaScript?

Question

const game = {
  team1: 'Bayern Munich',
  team2: 'Borrussia Dortmund',
  players: [
    [
      'Neuer',
      'Pavard',
      'Martinez',
      'Alaba',
      'Davies',
      'Kimmich',
      'Goretzka',
      'Coman',
      'Muller',
      'Gnarby',
      'Lewandowski',
    ],
    [
      'Burki',
      'Schulz',
      'Hummels',
      'Akanji',
      'Hakimi',
      'Weigl',
      'Witsel',
      'Hazard',
      'Brandt',
      'Sancho',
      'Gotze',
    ],
  ],
  score: '4:0',
  scored: ['Lewandowski', 'Gnarby', 'Lewandowski', 'Hummels'],
  date: 'Nov 9th, 2037',
  odds: {
    team1: 1.33,
    x: 3.25,
    team2: 6.5,
  },
};

1) Loop over the game.scored array and print each player name to the console,along with the goal number start from 1 like (Goal 1: etc)

This is my first solution and the result is perfect:

for (const [i, v] of game.scored.entries()) 
{
  console.log(`Goal: ${i + 1} ${v}`);
}

Output:

Goal: 1 Lewandowski

Goal: 2 Gnarby

Goal: 3 Lewandowski

Goal: 4 Hummels

Picture Result: enter image description here

The issue is when I tried from different method using Object.entries() the itration don't start from 1

Soultion 2

for (const [i, v] of Object.entries(game.scored)) 
{
  console.log(`Goal: ${i+1} ${v}`);
}

Output:

Goal: 01 Lewandowski

Goal: 11 Gnarby

Goal: 21 Lewandowski

Goal: 31 Hummels

Picture Result: enter image description here

Finally, I got my answer: In the array, we use the entries method but in the object, we have to use the object.entries() method and then pass into the function, the object that we are interested in. — Hamza Ilyas
– Hamza Ilyas, Commented Dec 31, 2020 at 12:44

Nina Scholz · Accepted Answer · 2020-12-31 12:28:09Z

The first approach takes the array and its entries (Array#entries), whereas the second one takes the object and the entries from the object (Object.entries).

Objects has only strings or symbols as keys. To take a number as value you need to convert it to a number. The shortest way is to take an unary plus +.

const
    game = { team1: 'Bayern Munich', team2: 'Borrussia Dortmund', players: [['Neuer', 'Pavard', 'Martinez', 'Alaba', 'Davies', 'Kimmich', 'Goretzka', 'Coman', 'Muller', 'Gnarby', 'Lewandowski'], ['Burki', 'Schulz', 'Hummels', 'Akanji', 'Hakimi', 'Weigl', 'Witsel', 'Hazard', 'Brandt', 'Sancho', 'Gotze']], score: '4:0', scored: ['Lewandowski', 'Gnarby', 'Lewandowski', 'Hummels'], date: 'Nov 9th, 2037', odds: { team1: 1.33, x: 3.25, team2: 6.5 } };


for (const [i, v] of Object.entries(game.scored)) {
    console.log(`Goal: ${+i + 1} ${v}`);
}

Yousaf · Accepted Answer · 2020-12-31 12:41:18Z

game.scored.entries() returns an iterator object in which the indexes are returned as numbers. So adding 1 to the value of i performs the addition and gives you the expected result.

Object.entries(game.scored) returns the key as a string. So when you do i + 1 in the second code example, instead of doing an addition, your code performs concatenation. Since i is a string, 1 will be converted to string and then concatenated with the value of i.

To get the desired result, convert i to a number before adding 1 to it.

There are multiple ways to convert a string to a number. You can use one of the following ways:

Using + unary operator

for (const [i, v] of Object.entries(game.scored)) 
{
  console.log(`Goal: ${(+i)+1} ${v}`);
}

Using parseInt() function

for (const [i, v] of Object.entries(game.scored)) 
{
  console.log(`Goal: ${parseInt(i) + 1} ${v}`);
}

Using Number() constructor

for (const [i, v] of Object.entries(game.scored)) 
{
  console.log(`Goal: ${Number(i) + 1} ${v}`);
}

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