查找对象数组的索引

Question

I'm stuck with the code. I actually want to find the index of elements in dataLayer using typescript/javascript.

track: { products },
dataLayers: { current: { cart: { items } } }

products?: IProduct[]

export interface IProduct {
    id: string
    quantity?: string
    name?: string
}
items?: ICartItem[]

export interface ICartItem {
    id: string
    brand: string
    name: string
    quantity: number

}

track: { products }

products have {id,quantity}

dataLayers: { current: { cart: { items } } }

items have {id, brand, name, quantity }

Now I want to find the position/index of products, For Example:

Example: *

products:{
[{id: 'a123',quantity: '1'},{id:'a345', quantity:'2'}]
}

items:{
[{id: 'a123',brand:'pen',name: 'Reynolds', quantity: '1'}, {id: 'a143',brand:'pencil',name: 'Nataraj', quantity: '3'}, {id: 'a122',brand:'pen',name: 'Parker',quantity: '1'},{id:'a345',brand:'Eraser',name: 'Faber-Castell', quantity:'2'}]
}

position of {id: 'a123',quantity: '1'} should be 1 and position of {id:'a345', quantity:'2'} should be 4

My code looks like below:

I have used map to get id from products as shown

const id = products.map(product => { return product.id})

now I want to find index/position of those products in items.so I tried like below

    let position = filter((item: ICartItem) => {
        if(id.includes(item.id)){
            return {id}
        }  
}).findindex(id)

ie,

    const id = products.map(product => { return product.id})
    let position = filter((item: ICartItem) => {
        if(id.includes(item.id)){
            return {id}
        }  
}).findindex(id)

but I getting error

Argument of type 'string[]' is not assignable to parameter of type '(value: ICartItem, index: number, obj: ICartItem[]) => unknown'. Type 'string[]' provides no match for the signature '(value: ICartItem, index: number, obj: ICartItem[]): unknown'.ts(2345)

an Some help me in finding position/index of the filtered product?

Answer 1

After map you can chain .indexOf() to get the Index of the object and Index of a345 would be 3 not 4 because indexes are zero based in an array

 let items = [{ id: 'a123', brand: 'pen', name: 'Reynolds', quantity: '1' }, { id: 'a143', brand: 'pencil', name: 'Nataraj', quantity: '3' }, { id: 'a122', brand: 'pen', name: 'Parker', quantity: '1' }, { id: 'a345', brand: 'Eraser', name: 'Faber-Castell', quantity: '2' }] let index= items.map(function(e) { return e.id; }).indexOf('a345') console.log(`Index=${index}`) console.log(`position= ${index+1}`)

Answer 2

You can chain map and indexOf to get result as an array with positions.

 const products = [ { id: 'a123', quantity: '1' }, { id: 'a345', quantity: '2' }, ]; const items = [ { id: 'a123', brand: 'pen', name: 'Reynolds', quantity: '1' }, { id: 'a143', brand: 'pencil', name: 'Nataraj', quantity: '3' }, { id: 'a122', brand: 'pen', name: 'Parker', quantity: '1' }, { id: 'a345', brand: 'Eraser', name: 'Faber-Castell', quantity: '2' }, ]; const result = products.map(product => items.map(item => item.id).indexOf(product.id) + 1); console.log(result)

If array with positions needs to return id as well then you can do:

 const products = [ { id: 'a123', quantity: '1' }, { id: 'a345', quantity: '2' }, ]; const items = [ { id: 'a123', brand: 'pen', name: 'Reynolds', quantity: '1' }, { id: 'a143', brand: 'pencil', name: 'Nataraj', quantity: '3' }, { id: 'a122', brand: 'pen', name: 'Parker', quantity: '1' }, { id: 'a345', brand: 'Eraser', name: 'Faber-Castell', quantity: '2' }, ]; const result = products.map(product => { const id = product.id; return { id, position: items.map(item => item.id).indexOf(id) + 1 } }); console.log(result)

Answer 3

You can try:

const ids = products.map( product => product.id);
const positions = items.map( ( item, i ) => {
  if( ids.includes(item.id)){
    return{
      position: i + 1,
      id: item.id
    }
  }
  return null
}).filter(Boolean)

//[ { position: 1, id: 'a123' }, { position: 4, id: 'a345' } ]