javascript - Nested array of objects filtering returns undefined in JS

Question

I am trying for each product check if tags array of objects has at least one tag of shows.

const allProducts = this.products.forEach(product =>
        product.tags.some(item => item.tagName !== 'shows'),
      )

Data sample:

    Products: [
    {
    productId:...
    productName: ...
    tags:[
    {
    tagId:...
    tagName:...
    }
    {
    tagId:...
    tagName:...
    }
    ]
    },
    {
    productId:...
    productName: ...
    tags:[
    {
    tagId:...
    tagName:...
    }
    {
    tagId:...
    tagName:...
    }
    ]
    }

]

It seems after some() it doesn't work. What is wrong and how can be it fixed?

question from:https://stackoverflow.com/questions/65935319/nested-array-of-objects-filtering-returns-undefined-in-js

Answer 1

Firstly, forEach does not return anything. So you should use .filter instead.

for each product check if the tags array of objects has at least one tag of shows.

Secondly, the condition should be === instead of !==, Besides, need return the true if all products are passing the some() not filter

==> Solution:

const allValidProducts = this.products.filter(product => product.tags.some(item => item.tagName === 'shows'));
const result =  allValidProducts.length === this.products.length;  

So as you can see, the .some works fine.

const array = [1, 2, 3, 4, 5];
console.log(array.some(element => element % 2 === 0));
// expected output: true