I have an object like this

const obj = {
  name: "abc",
  arr: [{
    key1: "value1",
    arr1: [1, 2, 3]
  }, {
    key2: "value2",
    arr2: [4, 5, 6]
  }]
}

Here, i want to add the lengths of arrays arr1 and arr2, and return 6 as an answer. I know looping and calculating lenghts by for-in is one solution, but what can be a faster and more precise solution?

CodePudding user response：

It looks you want to count the lengths of arrays that only have primitive values as members, not of arrays which have (some) objects/arrays as members.

Here is a proposed recursive solution:

const isPrimitive = val => Object(val) !== val;
const isArrayOfPrimitive = arr => arr?.every?.(isPrimitive);

const deepLength = obj => isPrimitive(obj) ? 0
         : Object.values(obj).reduce((sum, val) => sum   deepLength(val), 
                                     isArrayOfPrimitive(obj) ? obj.length : 0);

// Example run:
const obj = {
  name: "abc",
  arr: [{
    key1: "value1",
    arr1: [1, 2, 3]
  }, {
    key2: "value2",
    arr2: [4, 5, 6]
  }]
};

console.log(deepLength(obj)); // 6

CodePudding user response：

const obj = {
    name: "abc",
    arr: [
        { key1: "value1", arr1: [1, 2, 3, 4, 6, 7, 9] },
        { key2: "value2", arr2: [4, 5, 6] }
    ]
}



function getNumbers(arr) {
    let a = arr['arr'][0].arr1.length;
    let b = arr['arr'][1].arr2.length;

    let sum = a   b;
    return sum;
}

console.log(getNumbers(obj));