How to get all properties values of a Javascript Nested Objects (without knowing the keys)?

Question

In referencing how to do this i took a look at how-to-get-all-properties-values-of-a-javascript-object-without-knowing-the-key Using ES6

How would you do this if the object you are scanning into has child object where you need only the Values for those too, into an array.

example :

var errorData = {"Message":"The request is invalid.","ModelState":{"account.Contact.PrimaryPhone":["Primary Phone is required.","'Primary Phone' should not be empty."]}}

var errors = Object.keys(errorData).map(function (key) {
      return errorData[key];
});

doesn't work.

i need an array that lists like this:

The request is invalid.
Primary Phone is required.
'Primary Phone' should not be empty.

score 2 · Answer 1 · answered Mar 29 '18 at 18:10

2

There usually is a fixed structure to an API response, or at least a certain guideline. You could test for the type of the value, and see if it is an array or object. You could also anticipate a particular key in the response, test for its existence, and do work accordingly.

answered Mar 29 '18 at 18:10

Abderrahmane TAHRI JOUTI

3,514
2
26
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the structure fluctuates because fluent validation is used.. and depending on the child object it creates messages for each different object. In this case only Message, and ModelState are known... not account.Contact.PrimaryPhone for example – user1161137 Mar 29 '18 at 18:17

score 2 · Accepted Answer · answered Mar 29 '18 at 18:19

The easiest way is probably with a recursive function. You can do that like this in a modern engine:

const errorData = {"Message":"The request is invalid.","ModelState":{"account.Contact.PrimaryPhone":["Primary Phone is required.","'Primary Phone' should not be empty."]}}

const errors = (function flattenValues( obj ) {
  return Object.values( obj ).reduce(
    ( values, value ) => values.concat( typeof value === "object" ? flattenValues( value ) : value )
  , [ ] );
} )( errorData );

console.log( errors );

although Object.values only has fairly recent browser support, so you may want to use something that has more compatibility instead:

var errorData = {"Message":"The request is invalid.","ModelState":{"account.Contact.PrimaryPhone":["Primary Phone is required.","'Primary Phone' should not be empty."]}}

var errors = (function flattenValues( obj ) {
  return Object.keys( obj ).reduce( function ( keys, key ) {
    var value = obj[key];
    return values.concat( typeof value === "object" ? flattenValues( value ) : value );
  }, [ ] );
} )( errorData );

console.log( errors );

sellmeadog · Answer 3 · 2018-03-29T22:50:45.607

0

This should work. Just through it together, haven't fully tested it.

Object.values(a)
  .map(v => v instanceof Object ? Object.values(v) : [v])
  .reduce((acc, next) => acc.concat(...next), [])

edited Mar 29 '18 at 22:50

answered Mar 29 '18 at 18:26

sellmeadog

7,437
1
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This won't flatten the inner arrays. – Dan Nagle Mar 29 '18 at 18:43
You're right. I forgot to spread `next`. Updated accordingly. – sellmeadog Mar 29 '18 at 22:51

score 0 · Answer 4 · answered Mar 29 '18 at 18:39

let errorData = {"Message":"The request is invalid.","ModelState":{"account.Contact.PrimaryPhone":["Primary Phone is required.","'Primary Phone' should not be empty."]}}

const flatten = (obj) => obj.reduce((acc, val) => acc.concat(val), []);

const unwrap = (obj) => 
    Object.keys(obj).map((key) => { 
        if (typeof(obj[key]) == 'object') 
            return flatten(unwrap(obj[key]));
        else
            return obj[key];
    });

let errors = flatten(unwrap(errorData));

How to get all properties values of a Javascript Nested Objects (without knowing the keys)?

4 Answers4