Find all matching elements within an array of objects with unknown key-CodePudding

I have an array of objects like this:

[
    {"firstKey":"firstValue","secondKey":"secondValue"},
    {"thirdKey":"thirdValue","forthKey":"forthValue"}
]

and object like

{"thirdKey":"thirdValue","forthKey":"forthValue"}

I want to check if this object exists in an array of objects or no
NOTE: The keys of objects are generated dynamically and I don't know the name of the keys.

CodePudding user response：

SOLUTION: (only works when two the keys are in same order)

Use find() and JSON.stringify()

const arr = [
    {"firstKey":"firstValue","secondKey":"secondValue"},
    {"thirdKey":"thirdValue","forthKey":"forthValue"}
];

const look = {"thirdKey":"thirdValue","forthKey":"forthValue"}
const look2 = {"thirdKey":"fourthValue","forthKey":"forthValue"}

let exists1 = arr.find((x) => JSON.stringify(x) === JSON.stringify(look)) === undefined ? false : true ;

let exists2 = arr.find((x) => JSON.stringify(x) === JSON.stringify(look2)) === undefined ? false : true ;

console.log(exists1);
console.log(exists2);

EDIT:

JSON.stringify(x) === JSON.stringify(y) will only work when strings are in same order. Otherwise you will have to use a complex function to compare the two objects. Check

CodePudding user response：

You can use JSON.stringify() to compare objects:

const arr = [
    {"firstKey":"firstValue","secondKey":"secondValue"},
    {"thirdKey":"thirdValue","forthKey":"forthValue"}
]

const needle = {"thirdKey":"thirdValue","forthKey":"forthValue"}

console.log( arr.filter(o => JSON.stringify(o) === JSON.stringify(needle)) )

CodePudding user response：

What you need to do is get the keys of the object, using Object.keys(object), and for every object in the array do the same, than compare them, as follows:

function findEqual(object, array) {
    var objectKeys = Object.keys(object);
    for (var i = 0; i < array.length; i  ) {
        var currObjectKeys = Object.keys(array[i]);
        if (currObjectKeys.length !== objectKeys.length) {
            continue;
        }
        var found = true;

        for (var j = 0; j < objectKeys.length; j  ) {
            if (objectKeys[j] !== currObjectKeys[j]) {
                found = false;
                break;
            }
            if (object[objectKeys[j]] !== array[i][objectKeys[j]]) {
                found = false;
                break;
            }
        }
        if (found) {
            return i;
        }
    }
    
    return -1;
}

CodePudding user response：

const objExist = (arr, obj) => {
 return arr.reduce((acc, item)=>{
   const found = JSON.stringify(item) === JSON.stringify(obj); 
   if (found) { acc = 1}
   return acc
   }, 0)
}