How to break down an array of objects within a string

Question

I have some code that returns something like this:

body: '[
    {
        name: "name",
        lastname: "lastname"
    },
    {
        name: "name",
        lastname: "lastname"
    },
    {
        name: "name",
        lastname: "lastname"
    }
]'

Of course extracting the body is a simple object.body however, to get rid of the '' that wraps the array is just destroying me. I tried doing object.body.slice(1,-1) to get rid of them, it didnt work. I'm clearly not using the object properly.

How can I "extract" the array from within the body into a usable array?

Where is that data coming from? Can you control its form? If you would get valid JSON, you could use JSON.parse — lumio
– lumio, Commented Aug 20, 2017 at 19:35

spanky · Accepted Answer · 2017-08-20 19:31:11Z

2

It sounds like you want to evaluate the content of the string. Assuming whatever code building this string can't actually build JS objects to begin with, you can use eval or Function to generate the objects you need.

var data = eval(string);

Note that you must be sure that the source of the string is safe and reliable, otherwise you could be evaluating malicious code. There may also be performance consequences to using eval.

Using Function is a tiny bit safer, only because the code can not access your local variables. It should also avoid the performance costs of eval.

var data = Function("return (" + string + ");")();

Same warning about malicious code though.

If the string data was valid JSON, you could use JSON.parse, but it isn't, so you can't. To avoid security issues, either have the source provide valid JSON data, or write your own minimal parser to parse the data.

answered Aug 20, 2017 at 19:31

spanky

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8 Comments

techfly Over a year ago

There must be another way. eval is never a good idea, not even if you're 100% sure (because you can't be)

spanky Over a year ago

@Aenadon: eval/Function is a very good idea in those circumstances where you can guarantee safety. Don't play the "never" game. Instead be informed. My answer gives the necessary warnings.

Roman Over a year ago

@Aenadon in this situation this is a good idea. Eval will interpret the string to generate a array based on the string.

lumio Over a year ago

No! eval should never be used without sanitizing the given parameter!

spanky Over a year ago

@lumio: eval is a useful tool, as long as you know when to use it. Knowledgeable programmers don't need to resort to these knee-jerk reactions. You do yourself and others a disservice with such extreme overreactions.

|

Nina Scholz · Accepted Answer · 2017-08-20 19:39:13Z

0

With a valid JSON string, you could just parse the string for an object with JSON.parse, if you have .

array = JSON.parse(string);

edited Aug 20, 2017 at 19:39

answered Aug 20, 2017 at 19:29

Nina Scholz

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4 Comments

user1726343 Over a year ago

You can't do that, since the keys are not quoted.

Adi219 Over a year ago

You Ninja'd me :-(

Gal Appelbaum Over a year ago

Parse actually worked. I apologize for the RIDICULOUSLY STUPID question. been coding for 9 hrs straight today and my brain just can't process anymore. I'll accept the answer asap and upvote all of you friends :)

user1726343 Over a year ago

@GalAppelbaum Either the string you've posted in your question doesn't reflect your actual data, or JSON.parse won't work. The string in the question is not valid JSON, since the keys of the objects are not enclosed in double quotes.

Sh Ndrukaj · Accepted Answer · 2017-08-20 19:36:06Z

0

You can use split function and then take the first element, let me say

var a = '[{name: "name",lastname: "lastname"},{name: "name",lastname: "lastname"},{name: "name",lastname: "lastname"}]';
    var s = a.split("'");

s[0] will return you the desired result

answered Aug 20, 2017 at 19:36

Sh Ndrukaj

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2 Comments

Orkhan Alikhanov Over a year ago

The variable a does not contain single quote '. What are you splitting then?

Sh Ndrukaj Over a year ago

sorry, it's my mistake! What i mean is that suppose var a is a string containing those single quotes as your situation is! so in this case var a = '\'[{name: "name",lastname: "lastname"},{name: "name",lastname: "lastname"},{name: "name",lastname: "lastname"}]\''; var s = a.split("'"); s[1] will be the wanted result!

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