Best way to find whether a value exists in a JSON object in javascript?

Question

I have a single level JSON to search through for the presence of a given value. Is there is a compact method provided in ecma5 for the same ?

Answer 1

1. Parse the JSON string with JSON.parse to get a JavaScript Object.

2. Use in operator to check the member existence

   var jsObj = JSON.parse('{"p": 5}');
   console.log(jsObj);
   if ("p" in jsObj) {
       console.log("`p` exists");
   }
   

   Output

   { p: 5 }
   `p` exists
   

Answer 2

Since it sounds like you're looking for a specific value in an unknown key, assuming there that you already parsed your JSON, you'll need something more like:

function valueExists(jsObj, value){
    for (var key in jsObj){
        if (jsObj[key] == value) return true;
    }
    return false;
}

Answer 3

Parse the JSON string with JSON.parse to get a JavaScript Object, and do

Simplest check,

if(jsonObj['key']) {
}

Working fiddle