Iterate over the key-value pairs in a loop

Question

Iterate over the key-value pairs in a loop

How can I iterate through a key-value pair array?

This is how I declare mine:

products!: {[key: string] : ProductDTO}[];

Here's my loop:

for (let product of this.products) {
  category.products.push((product as ProductDTO).serialize());
}

However, I encounter this error:

Converting type '{ [key: string]: ProductDTO; }' to type 'ProductDTO' might be an error

I also attempted:

for (let product of Object.values(this.products))

But encountered the same issue.

javascript typescript

Answer 1

Answer №1

this.produse is an array containing objects of type

Array<{[key: string] : ProductDTO}>

. The presence of [] at the end signifies that it is indeed an array. To properly loop through this structure, you must first iterate over the array and then access each individual object:

for (const produses of this.produse) {
  for (const produs of Object.values(produses)) {
    category.produse.push(produs.toSerialized());
  }
}

An alternative way to achieve the same result is by utilizing the flatMap method:

const serialized = this.produse.flatMap(
  produses => Object.values(produses).map(v => v.toSerialized())
);

// Rewrite category.produse
category.produse = serialized;

// Alternatively, add new products while retaining existing ones
category.produse.push(...serialized);

Answer 2

this.produse is an array containing objects of type

Array<{[key: string] : ProductDTO}>

. The presence of [] at the end signifies that it is indeed an array. To properly loop through this structure, you must first iterate over the array and then access each individual object:

for (const produses of this.produse) {
  for (const produs of Object.values(produses)) {
    category.produse.push(produs.toSerialized());
  }
}

An alternative way to achieve the same result is by utilizing the flatMap method:

const serialized = this.produse.flatMap(
  produses => Object.values(produses).map(v => v.toSerialized())
);

// Rewrite category.produse
category.produse = serialized;

// Alternatively, add new products while retaining existing ones
category.produse.push(...serialized);

Answer 3

Answer №2

After experimenting with different syntax options, I found that the code snippet below was effective in achieving the desired outcome, although I believe there might be a more elegant solution.


 for(let item of this.items){
      category.items.push((Object.values(item)[0] as ItemDTO).toSerialized())
}

Answer 4

After experimenting with different syntax options, I found that the code snippet below was effective in achieving the desired outcome, although I believe there might be a more elegant solution.


 for(let item of this.items){
      category.items.push((Object.values(item)[0] as ItemDTO).toSerialized())
}

Answer 5

Answer №3

To achieve the desired outcome, you will need to utilize two nested loops:

for (const itemMap of this.items) {               // itemMap represents a collection of key-value pairs containing ProductDTO data
  const itemList = Object.values(itemMap);         // itemList holds an array of ProductDTO objects
  for (const item of itemList) {                   // item represents a single ProductDTO object
    category.items.push(item.serialize());
  }
}

Answer 6

To achieve the desired outcome, you will need to utilize two nested loops:

for (const itemMap of this.items) {               // itemMap represents a collection of key-value pairs containing ProductDTO data
  const itemList = Object.values(itemMap);         // itemList holds an array of ProductDTO objects
  for (const item of itemList) {                   // item represents a single ProductDTO object
    category.items.push(item.serialize());
  }
}

Iterate over the key-value pairs in a loop

Answer №1

Answer №2

Answer №3

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