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.

Paul · Accepted Answer · 2018-03-29 18:19:23Z

2

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 );

answered Mar 29, 2018 at 18:19

Paul

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1 Comment

user1161137 Over a year ago

tx U ... perfect!

Abderrahmane TAHRI JOUTI · Accepted Answer · 2018-03-29 18:10:39Z

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, 2018 at 18:10

Abderrahmane TAHRI JOUTI

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1 Comment

user1161137 Over a year ago

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

Dan Nagle · Accepted Answer · 2018-03-29 18:39:31Z

0

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));

answered Mar 29, 2018 at 18:39

Dan Nagle

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Comments

sellmeadog · Accepted Answer · 2018-03-29 22:50:45Z

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, 2018 at 22:50

answered Mar 29, 2018 at 18:26

sellmeadog

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2 Comments

Dan Nagle Over a year ago

This won't flatten the inner arrays.

sellmeadog Over a year ago

You're right. I forgot to spread next. Updated accordingly.

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