Parse JSON data in javascript

Question

I have a service called UserService that returns the roles of the logged in user.

It returns either [{"authority":"ROLE_APEX_SUPPORT"},{"authority":"ROLE_APEX_READONLY"}] or [{"authority":"ROLE_APEX_READONLY"}].

I want to do something when I see that the response returned has ROLE_APEX_SUPPORT authority in it. How do I parse the response to identify that?

let listOfAuthorities = this.userServices.getAuthorities();

listOfAuthorities is an array of JSON of above mentioned response. How do I parse and see if it has Support role in response?

Possible duplicate of [How to parse JSON using Node.js?](https://stackoverflow.com/questions/5726729/how-to-parse-json-using-node-js) — Ayush Gupta, Sep 12 '19 at 09:59
Possible duplicate of [Javascript how to parse JSON array](https://stackoverflow.com/questions/9991805/javascript-how-to-parse-json-array) — François Huppé, Sep 12 '19 at 10:00

score 1 · Answer 1 · answered Sep 12 '19 at 10:06

I want to do something when I see that the response returned has ROLE_APEX_SUPPORT authority in it

If I understand your question correctly, you probably want to check if your array has an item with authority: ROLE_APEX_SUPPORT

const input1 = [{
  "authority": "ROLE_APEX_SUPPORT"
}, {
  "authority": "ROLE_APEX_READONLY"
}];

const input2 = [{
  "authority": "ROLE_APEX_READONLY"
}];

function hasAuthority(input, authority) {
  return input.some((i) => i.authority === authority);
}

console.log(hasAuthority(input1, "ROLE_APEX_READONLY"))
console.log(hasAuthority(input2, "ROLE_APEX_SUPPORT"))

score 1 · Answer 2 · answered Sep 12 '19 at 10:07

With a little effort you could have found the answer yourself. But, here it is:

let listOfAuthorities = this.userServices.getAuthorities();
let authorityList = JSON.parse(listOfAuthorities);

authorityList.forEach(authority => {
    if(authority.authority === 'ROLE_APEX_SUPPORT') {
    // write your logic here
    }
});

StepUp · Accepted Answer · 2019-09-12T11:26:24.137

To check whether your data contains ROLE_APEX_SUPPORT:

const json = [{"authority":"ROLE_APEX_SUPPORT"}, {"authority":"ROLE_APEX_READONLY"}];
const isROLE_APEX_SUPPORT = json.some(s=>s.authority === 'ROLE_APEX_SUPPORT');
console.log(isROLE_APEX_SUPPORT); // Output: true

To find whether your data contains ROLE_APEX_SUPPORT:

const json = [{"authority":"ROLE_APEX_SUPPORT"}, {"authority":"ROLE_APEX_READONLY"}];
const roleAlexSupport = json.find(s=>s.authority === 'ROLE_APEX_SUPPORT');
console.log(roleAlexSupport ); // OUTPUT: {authority: "ROLE_APEX_SUPPORT"}

In addition, you can use json.parse() method to parse JSON:

var json = '{"result":true, "count":42}';
obj = JSON.parse(json);

Parse JSON data in javascript

3 Answers3