How do I loop through json with arrays and get all the value?

Question

I have a JSON that looks like this:

{
"success": false,
"error": {
    "username": [
        "The username has already been taken."
    ],
    "email_address": [
        "The email address has already been taken."
    ]
}
}

I want to store all the messages in an array. Right now, I'm doing it manually by checking one by one. Is there a better way?

Possible duplicate of [Angular2 - \*ngFor / loop through json object with array](https://stackoverflow.com/questions/43215049/angular2-ngfor-loop-through-json-object-with-array) — Vivek Doshi, Feb 16 '18 at 13:20

felixmosh · Accepted Answer · 2018-02-16T13:16:12.960

1

You can use the Object.keys method that will return an array with the error keys. Then you can iterate it with any Array method such as map, forEach, reduce to collect the messages them-self.

const response = {
  "success": false,
  "error": {
    "username": [
      "The username has already been taken.",
      "Another message"
    ],
    "email_address": [
      "The email address has already been taken."
    ]
  }
};

const result = Object.keys(response.error)
  .reduce((acc, key) => acc.concat(response.error[key]), []);

console.log(result);

edited Feb 16 '18 at 13:16

answered Feb 16 '18 at 13:07

felixmosh

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Undefined values are stored in array, although the number is right. – Jonathan Lightbringer Feb 16 '18 at 13:13
So, I would use `reduce` in order to collect all the messages. will update my answer – felixmosh Feb 16 '18 at 13:15
Works like charm. – Jonathan Lightbringer Feb 16 '18 at 13:53

score 0 · Answer 2 · answered Feb 16 '18 at 13:05

This is how you can get all the messages in a array

var a = {
"success": false,
"error": {
    "username": [
        "The username has already been taken."
    ],
    "email_address": [
        "The email address has already been taken."
    ]
}
}
var keys = Object.keys(a['error'])
var errors = a['error']

var c = [];
for(var i=0; i< keys.length; i++){
    c.push(a['error'][keys[i]][0])
}
console.log(c)

How do I loop through json with arrays and get all the value?

2 Answers2