如何遍历嵌套对象并组合键和值？

Question

const products = {
  value: {
    phone: [],
    lamp: [],
    car: ["bmw", "toyota", "audi"]
  }
};

In the given object I want to iterate and get keys .
Note that values are array of strings .

I'd like to get all keys and if values are not empty arrays I want to combine with keys and return an array with this structure

   [
    phone,
    lamp,
    car-bmw,
    car-toyota,
    car-audi
  ]

Here is what I did so far, which is not what I want

 const products = { value: { phone: [], lamp: [], car: ["bmw", "toyota", "audi"] } }; const mappedProducts = Object.entries(products.value).map(([value, items]) => { //console.log("value:", value, "items:", items) if (items.length > 0) { return { car: items.map((c) => c) }; } }); console.log(mappedProducts);

Any help will be appreciated.

Answer 1

I modified what you did a bit, you can you flatMap

 const products = { value: { phone: [], lamp: [], car: ["bmw", "toyota", "audi"] } }; const mappedProducts = Object.entries(products.value).flatMap(([value, items]) => { //console.log("value:", value, "items:", items) if (items.length > 0) { return items.map(item => `${value}-${item}`); } else { return [value]; } }); console.log(mappedProducts);

Answer 2

You can use for in loop

 const products = { value: { phone: [], lamp: [], car: ["bmw", "toyota", "audi"] } }; const newData = []; for (const key in products) { const value = products[key]; for (const innerKey in value) { const innerVal = value[innerKey]; if (innerVal.length > 0) { innerVal.forEach((item) => newData.push(`${innerKey}-${item}`)); } else { newData.push(innerKey); } } } console.log(newData);

Answer 3

Another solution would be to use Object.keys() along with map and concat to get a merged array with keys and values (if any):

const products = {
  value: {
    phone: [],
    lamp: [],
    car: ["bmw", "toyota", "audi"]
  }
};

let keys = [].concat.apply([], Object.keys(products.value).map((key) =>{
    if(products.value[key].length > 0){
    return products.value[key];
  }
  else return key;
}));
console.log(keys);