how to build a new json string from existing json string

I have multiple files that contain json data that looks like this:

1.json:

[{
    "id": 2100059,
    "email": "",
    "company": "acme",
    "job_title": "",
    "first_name": "Jane",
    "last_name": "Doe"
 }, 
 {
    "id": 2199991,
    "email": "",
    "company": "Widgets Inc",
    "job_title": "",
    "first_name": "John",
    "last_name": "Doe"
 }]

2.json:

[{
    "id": 123456,
    "email": "",
    "company": "acme",
    "job_title": "",
    "first_name": "GI Jame",
    "last_name": "Adf"
 }, 
 {
    "id": 000001,
    "email": "",
    "company": "Widgets Inc",
    "job_title": "",
    "first_name": "bob",
    "last_name": "billy"
 }]

How can I combine these two lists so that it's just one string, with one set of []?

So far, I'm writing the logic read in the contents of each file into separate strings. But then I'm thinking I should: 1. json_decode() each string to treat it like an object

Not sure how to append to the object though. any tips would be appreciated.

EDIT 1

I decided to read each file contents into an array, and then try the tips suggested below to use array_merge. when i do a print_r on my array, it looks like this: (bogus data, but you should get the idea)

Array
(
    [0] => [{"id":2100059,"email":"","company":""},{"id":2129527,"email":"","company":""},{"id":2134804,"email":"","company":""},{"id":2148239,"email":"","company":""}]
    [1] => [{"id":2100059,"email":"","company":""},{"id":2129527,"email":"","company":""},{"id":2134804,"email":"","company":""},{"id":2148239,"email":"","company":""}]
[2] => [{"id":2100059,"email":"","company":""},{"id":2129527,"email":"","company":""},{"id":2134804,"email":"","company":""},{"id":2148239,"email":"","company":""}
[3] =>[{"id":2100059,"email":"","company":""},{"id":2129527,"email":"","company":""},{"id":2134804,"email":"","company":""},{"id":2148239,"email":"","company":""}]

)

And then this is the logic I have that tries to combine all this into one json string:

    print_r($allpages);

$finaljsonstring =‘’;

foreach ($allpages as $item)

{

$finaljsonstring = $finaljsonstring + json_encode(array_merge(json_decode($item)));

}

echo $finaljsonstring;

But something is going wrong. (I’m calling this as ajax so it’s hard to debug) but when i console.log the results from the ajax call, nothing is returned. Ultimately, what I need to return to the front end is a single array of json strings like this:

[{}, {},{}]

#php #json #ajax