How to access KeyValuePair collection as JSON array

Question

I'm making Ajax calls to a page in ASP.NET Core 3.1.

The response is a JsonResult whose Value property is an instance of a custom class, itself containing various string and collection properties.

One of these collections is a Dictionary<string, string>, which I can then access in JavaScript along the following lines:

var dictionary = response.DictionaryObj;

for (key in dictionary) {
    DoSomeStuff(key, dictionary[key]);
}

However another of these collections requires a non-unique 'key', and is currently a List<KeyValuePair>

This ends up in JavaScript as an array of objects, which I can access like this:

var kvps = response.KvpList;

for (i = 0; i < kvps.length; i++) {
   var kvp = kvps[i];
   DoSomeMoreStuff(kvp.key, kvp.value);
}

The latter seems far less elegant - is there a way of packaging up the KeyValuePairs in a way that would let me use the former syntax?

@Tx_monster The key can, yes. The keys represent actions, and the values are each a concatenated list of arguments. So the key can appear many times, with different values. The JS iterates through the list, unpacks the args and then carries out the actions. — ChrisA, Jun 08 '20 at 09:15
Ok, so you are using already the shortest and most elegant way. — Riccardo Manzan, Jun 09 '20 at 13:56

Nikita Madeev · Answer 1 · 2020-06-08T08:09:25.563

For Dictionary<string, string> you can use Object.entries()

For List<KeyValuePair> object destructuring

const dictionaryObj = {
    a: 'somestring',
    b: 42,
};

for (const [key, value] of Object.entries(dictionaryObj)) {
    console.log(`${key}: ${value}`); // DoSomeStuff(key, value)
}

console.log('===========================================');

const kvpList = [
    { key: '1', value: 'v1' },
    { key: '2', value: 'v2' },
    { key: '3', value: 'v3' },
];

for (const { key, value } of kvpList) {
    console.log(`${key}: ${value}`); // DoSomeMoreStuff(key, value)
}

StepUp · Accepted Answer · 2020-06-08T08:29:57.877

If you have an object and you want to iterate through its properties, then we can use Object.entries method to get an array of a given object's own enumerable string-keyed property [key, value] pairs, and then just use loop foreach:

let input =  { "workType": "NDB To Nice", "priority": 5, "name": "Joseph", "lastName": "Skeet" }


const fooFunctiion = (key, value) => {
  console.log(`key: ${key}, value ${value}` )
}

Object.entries(input).forEach(([k, v]) => {
    fooFunctiion(k, v)
});

If you have an array of objects, then you can use foreach method:

let input = [
  { "workType": "NDB To Nice", "priority": 5 },
  { "workType": "PDAD", "priority": 0 },
  { "workType": "PPACA", "priority": 0 },
  { "workType": "Retrigger", "priority": "5" },
  { "workType": "Special Intake Request Intake", "priority": "7" }
];

const fooFunction = (obj, index) => {
  console.log('obj: ', obj, index )
}

input.forEach((obj, ind) =>
    fooFunction(obj, ind)
);

How to access KeyValuePair collection as JSON array

2 Answers2