List of individual JavaScript object to proper array

Question

I've encountered a problem with conversion list of individual JavaScript object to proper JavaScript array.

The list looks like below:

{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }

So, as you can see there two things which I need to take care of:

Adding missing commas
Create array from it.

To parse this response I'm using node JS. I've tried to convert this to array as follows:

const array = `[${response.data}.replace(/}/g, '},')}{}]`

Firstly I'm wrapping everything with array, add commas, and one empty object to get rid of last unwanted comma.

If I look at output everything seems ok, but when I'm trying to parse it with JSON.parse() I'm receiving

Unexpected ']' on position n

I'm not sure whether I'm doing something wrong or that data is corrupted since it is so long.

Fix what the server returns, that should already be valid JSON. — connexo
– connexo, Commented May 17, 2019 at 7:59
It looks like you may be building your JSON manually server-side, you probably should instead build a proper array and use JSON encoding function to export it — Kaddath
– Kaddath, Commented May 17, 2019 at 8:04

CertainPerformance · Accepted Answer · 2019-05-17 08:01:08Z

3

You can use a regular expression to add commas to the end of every line but the last, change someArray to "someArray", then surround the whole string in [] and JSON.parse it:

const response = `{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }
{ "property1": "value", someArray: [123], "property2": [] }`;

const json = '[' + response.replace(/}(?!$)/g, '},').replace(/someArray/g, '"$&"') + ']';
const arr = JSON.parse(json);
console.log(arr);

But this is still an X/Y problem - better to fix whatever's serving you that (effectively broken) data to get it to give you proper JSON instead, so that a hack like this isn't needed.

answered May 17, 2019 at 8:01

CertainPerformance

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Nina Scholz · Accepted Answer · 2019-05-17 08:00:34Z

1

You need to omit the last comma and look ahead if some more characters are coming.

const array = `[${response.data}.replace(/}(?=.)/g, '},')}{}]`;
//                                         ^^^^^

answered May 17, 2019 at 8:00

Nina Scholz

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Carsten · Accepted Answer · 2019-05-17 08:18:52Z

If you really cannot modify the response of this list, you can use this:

const array = response.data.split(/\r?\n/).map(object => JSON.parse(object.replace("someArray", "\"$&\"")));

Each line will be split by split(/\r?\n/) and replace("someArray", "\"$&\"") will add the missing double quotes around someArray.

Working example:

const response = {
  "data": `{ "property1": "value", someArray: [123], "property2": [] }
           { "property1": "value", someArray: [123], "property2": [] }
           { "property1": "value", someArray: [123], "property2": [] }
           { "property1": "value", someArray: [123], "property2": [] }
           { "property1": "value", someArray: [123], "property2": [] }`
}

const array = response.data.split(/\r?\n/).map(line => JSON.parse(line.replace("someArray", "\"$&\"")));

console.log(array);

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