Give a try with this code to save each element with names 0.json, 1.json and 2.json. FYI, it can work for any number of JSON items in an array.

for i in (jq '.|length' sample.json)); do \
    j=$( expr $i - 1 ); \
    jq ".[$j]" sample.json > $j.json;  \
done

Explanation:

below line finds the length of array to name the objects:

(jq '.|length' sample.json))

Since the array starts with 0, lets fix the output file name

j=$( expr $i - 1 );

below lines fetches one element from json document and save to file

jq ".[$j]" sample.json > $j.json;

to save literally to x.json, y.json and z.json:

for i in x y z; do \
  jq ".[$count]" sample.json > $i.json;  \
  count=$( expr $count + 1 ) \
done

Answering the question whether Python or Node will be better for the task would be an opinion and we are not allowed to voice our opinions on Stack Overflow. You have to decide yourself what you have more experience in and what you want to work with - Python or Node.

If you go with Node, there are some modules that can help you with that task, that do streaming JSON parsing. E.g. those modules:

• https://www.npmjs.com/package/JSONStream
• https://www.npmjs.com/package/stream-json
• https://www.npmjs.com/package/json-stream

If you go with Python, there are streaming JSON parsers here as well:

• https://github.com/kashifrazzaqui/json-streamer
• https://github.com/danielyule/naya
• http://www.enricozini.org/blog/2011/tips/python-stream-json/

Using jq, one can split an array into its components using the filter:

.[]

The question then becomes what is to be done with each component. If you want to direct each component to a separate file, you could (for example) use jq with the -c option, and filter the result into awk, which can then allocate the components to different files. See e.g. Split JSON File Objects Into Multiple Files

Performance considerations

One might think that the overhead of calling jq+awk would be high compared to calling python, but both jq and awk are lightweight compared to python+json, as suggested by these timings (using Python 2.7.10):

time (jq -c  .[] input.json | awk '{print > "doc00" NR ".json";}')
user    0m0.005s
sys     0m0.008s

time python split.py
user    0m0.016s
sys     0m0.046s

I ran into this problem today as well, and did some research. Just want to share the resulting Python snippet that lets you also customise the length of split files (thanks to this slicing method).

import os
import json
from itertools import islice

def split_json(
    data_path,
    file_name,
    size_split=1000,
):
    """Split a big JSON file into chunks.
    data_path : str, "data_folder"
    file_name : str, "data_file" (exclude ".json")
    """
    with open(os.path.join(data_path, file_name + ".json"), "r") as f:
        whole_file = json.load(f)

    split = len(whole_file) # size_split

    for i in range(split + 1):
        with open(os.path.join(data_path, file_name + "_"+ str(split+1) + "_" + str(i+1) + ".json"), 'w') as f:
            json.dump(dict(islice(whole_file.items(), i*size_split, (i+1)*size_split)), f)
    return

Update: Then, when you need to combine them together again, use the following code:

json_all = dict()
split = 4         # this is the 1-based actual number of splits

for i in range(1, split+1):
    with open(os.path.join("data_folder", "data_file_" + str(split) + "_" + str(i) + ".json"), 'r') as f:
        json_i = json.load(f)
        json_all.update(json_i)