如何在不嵌套 Object.entries 的情况下在 object 中添加值？

Question

My JSON looks something like this:

const json = {
  "08/23/2022": {
    "One": 254,
    "Two": 92,
    "Three": 8
  },
  "08/13/2022": {
    "One": 327,
    "Two": 86,
  },
  "08/14/2022": {
    "One": 431
  },
}

I need to add all of these values, regardless of what the key is. In this case, the calculation would be 254+92+8+327+86+431, and the output would be 1198. Previously I had just been counting the first ([0]) value but I just realized that's not correct and the only solution I can think of is essentially nesting loops, but that doesn't seem like the cleanest or most efficient way to accomplish this. This is my current code for reference:

for (const [key, value] of Object.entries(json)) {
  Object.entries(value).forEach(val => output += val[1])
}

So what's the correct way?

Answer 1

There are fundamentally two dimensions to go through - the date-object pairs of the top level object, and then the digit-number pairs of the inner objects. So there really isn't any decent way around logic that accounts for two levels of nesting.

But, a better approach would be to use Object.values - you don't care about the keys, only the values.

 const json = { "08/23/2022": { "One": 254, "Two": 92, "Three": 8 }, "08/13/2022": { "One": 327, "Two": 86, }, "08/14/2022": { "One": 431 }, }; const sum = Object.values(json).flatMap(Object.values).reduce((a, b) => a + b, 0); console.log(sum);

The result is 1198 because that's the result of 254+92+8+327+86+431.

Well, I suppose there's a way around using an Object or object iteration method twice (or more) - JSON.stringify will iterate over all nested properties anywhere - but that's silly and shouldn't be used in real code.

 const json = { "08/23/2022": { "One": 254, "Two": 92, "Three": 8 }, "08/13/2022": { "One": 327, "Two": 86, }, "08/14/2022": { "One": 431 }, }; let sum = 0;; JSON.stringify(json, (_, val) => { if (typeof val === 'number') sum += val; return val; }); console.log(sum);