CODEWITHSUNDEEP
javascriptarrays
Sudhir
Sudhir

Reputation: 579

Push an item to array of array in javascript

Hi I am having an array like below and trying to push the item on map, but i am not able to push, Please tell what wrong i am doing here.

firstClassPrices: [
  [
    "Kan ej ombokas",
    "431",
    "SEK",
    "Företagspris"
  ],
  [
    "Kan ombokas",
    "525",
    "SEK",
    "Företagspris"
  ]
]

trying to push '1' like below:

 let ticketi = firstClassPrices.map((price) => {
      price.push("1");
    });

i need o/p as

firstClassPrices: [
      [
        "Kan ej ombokas",
        "431",
        "SEK",
        "Företagspris",
         "1"
      ],
      [
        "Kan ombokas",
        "525",
        "SEK",
        "Företagspris",
         "1"
      ]
    ]

Upvotes: 1

Views: 69

Answers (4)

callback
callback

Reputation: 4122

You have to return the price

const firstClassPrices = [
  [
    "Kan ej ombokas",
    "431",
    "SEK",
    "Företagspris"
  ],
  [
    "Kan ombokas",
    "525",
    "SEK",
    "Företagspris"
  ]
];

 let ticketi = firstClassPrices.map((price) => {
      // skip if price already includes 1
      if (!price.includes("1")) {
        price.push("1");
      }
      return price;
    });

console.log(ticketi);

Upvotes: 3

Nina Scholz
Nina Scholz

Reputation: 386530

Your approach mutates the old array and maps undefined.

Instead, you could map the old and new content of the array.

This approach does not mutate the old data.

let ticketi = firstClassPrices.map(price => [...price, '1']);

Upvotes: 2

Ele
Ele

Reputation: 33726

Since you want to mutate the original arrays, you can use the function Array.prototype.forEach.

The problem you're facing is regarding the missing return value inside of the map's handler, so basically, the handler is returning undefined

const array = [  [    "Kan ej ombokas",    "431",    "SEK",    "Företagspris"  ],  [    "Kan ombokas",    "525",    "SEK",    "Företagspris"  ]],
      handler = (a) => a.push("1");

array.forEach(handler);

console.log(array);
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Upvotes: 1

Yosvel Quintero
Yosvel Quintero

Reputation: 19060

You can use Array.prototype.map() combined with Array.prototype.concat()

Code:

const firstClassPrices = [["Kan ej ombokas","431","SEK","Företagspris"],["Kan ombokas","525","SEK","Företagspris"]]

const ticketi = firstClassPrices.map(p => p.concat('1'))

console.log(ticketi)

Upvotes: 1

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