How to check if a value exists in an object using JavaScript

Shortest ES6+ one liner:

let exists = Object.values(obj).includes("test1");

You can use Object.values():

The Object.values() method returns an array of a given object's own enumerable property values, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).

and then use the indexOf() method:

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

For example:

Object.values(obj).indexOf("test`") >= 0

A more verbose example is below:

var obj = {
  "a": "test1",
  "b": "test2"
}


console.log(Object.values(obj).indexOf("test1")); // 0
console.log(Object.values(obj).indexOf("test2")); // 1

console.log(Object.values(obj).indexOf("test1") >= 0); // true
console.log(Object.values(obj).indexOf("test2") >= 0); // true 

console.log(Object.values(obj).indexOf("test10")); // -1
console.log(Object.values(obj).indexOf("test10") >= 0); // false

For a one-liner, I would say:

exist = Object.values(obj).includes("test1");
console.log(exist);

I did a test with all these examples, and I ran this in Node.js v8.11.2. Take this as a guide to select your best choice.

let i, tt;
    const obj = { a: 'test1', b: 'test2', c: 'test3', d: 'test4', e: 'test5', f: 'test6' };

console.time("test1")
i = 0;
for( ; i<1000000; i=i+1) {
  if (Object.values(obj).indexOf('test4') > -1) {
    tt = true;
  }
}
console.timeEnd("test1")

console.time("test1.1")
i = 0;
for( ; i<1000000 ; i=i+1) {
  if (~Object.values(obj).indexOf('test4')) {
    tt = true;
  }
}
console.timeEnd("test1.1")

console.time("test2")
i = 0;
for( ; i<1000000; i=i+1) {
  if (Object.values(obj).includes('test4')) {
    tt = true;
  }
}
console.timeEnd("test2")


console.time("test3")
i = 0;
for( ; i<1000000 ; i=i+1) {
  for(const item in obj) {
    if(obj[item] == 'test4') {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test3")

console.time("test3.1")
i = 0;
for( ; i<1000000; i=i+1) {
  for(const [item, value] in obj) {
    if(value == 'test4') {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test3.1")


console.time("test4")
i = 0;
for( ; i<1000000; i=i+1) {
  tt = Object.values(obj).some((val, val2) => {
    return val == "test4"
  });
}
console.timeEnd("test4")

console.time("test5")
i = 0;
for( ; i<1000000; i=i+1) {
  const arr = Object.keys(obj);
  const len = arr.length;
  let i2 = 0;
  for( ; i2<len ; i2=i2+1) {
    if(obj[arr[i2]] == "test4") {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test5")

Output on my server

test1:   272.325 ms
test1.1: 246.316 ms
test2:   251.98 0ms
test3:    73.284 ms
test3.1: 102.029 ms
test4:   339.299 ms
test5:    85.527 ms

if (Object.values(obj).includes('test1')){
   return true
}

you can try this one

var obj = {
  "a": "test1",
  "b": "test2"
};

const findSpecificStr = (obj, str) => {
  return Object.values(obj).includes(str);
}

findSpecificStr(obj, 'test1');

In new version if ecma script now we can check vslues by ?. operations..

Its so simpler and easy yo check values in a object or nested or objects

var obj = {
   "a": "test1",
   "b": "test2"
}

if(obj?.a) return "i got the value"

Similarly since in Javascript most used primitive type is Object

We can use this arrays, functions etc too

aFunc = () => { return "gotcha"; }

aFunc?.() // returns gotcha

myArray = [1,2,3]

myArray?.[3] // returns undefined

Thanks

Best way to find value exists in an Object using Object.keys()

obj = {
 "India" : {
 "Karnataka" : ["Bangalore", "Mysore"],
 "Maharashtra" : ["Mumbai", "Pune"]
 },
 "USA" : {
 "Texas" : ["Dallas", "Houston"],
 "IL" : ["Chicago", "Aurora", "Pune"]
 }
}

function nameCity(e){
    var finalAns = []
    var ans = [];
    ans = Object.keys(e).forEach((a)=>{
        for(var c in e[a]){
            e[a][c].forEach(v=>{
                if(v === "Pune"){
                    finalAns.push(c)
                }
            })

        }
    })
    console.log(finalAns)
}


nameCity(obj)

var obj = {"a": "test1", "b": "test2"};
var getValuesOfObject = Object.values(obj)
for(index = 0; index < getValuesOfObject.length; index++){
    return Boolean(getValuesOfObject[index] === "test1")
}

The Object.values() method returned an array (assigned to getValuesOfObject) containing the given object's (obj) own enumerable property values. The array was iterated using the for loop to retrieve each value (values in the getValuesfromObject) and returns a Boolean() function to find out if the expression ("text1" is a value in the looping array) is true.

getValue = function (object, key) {
    return key.split(".").reduce(function (obj, val) {
        return (typeof obj == "undefined" || obj === null || obj === "") ? obj : (_.isString(obj[val]) ? obj[val].trim() : obj[val]);}, object);
};

var obj = {
   "a": "test1",
   "b": "test2"
};

Function called:

 getValue(obj, "a");

For complex structures, here is how I do it:

const obj = {
    test: [{t: 't'}, {t1: 't1'}, {t2: 't2'}],
  rest: [{r: 'r'}, {r1: 'r1'}, {r2: 'r2'}]
}

console.log(JSON.stringify(obj).includes(JSON.stringify({r1: 'r1'}))) // returns true
console.log(JSON.stringify(obj).includes(JSON.stringify({r1: 'r2'}))) // returns false

_.has() method is used to check whether the path is a direct property of the object or not. It returns true if the path exists, else it returns false.

var object = { 'a': { 'b': 2 } };
console.log(_.has(object, 'a.b')); 
console.log(_.has(object, ['a','b'])); 
console.log(_.has(object, ['a','b','c']));

Output: true true false

The simple answer to this is given below.

This is working because every JavaScript type has a “constructor” property on it prototype”.

let array = []
array.constructor === Array
// => true


let data = {}
data.constructor === Object
// => true