javascript - Search and update value in json file in node js

Question

I'm trying to create a key-value paired datastore in nodejs in which I'm trying to use a json file as a database. Now I'm trying to read a particular value of key and update it or delete it.

For eg.(dummy data)

{
   name: 'my name',
   no:12345,
   course : {
      name: 'cname',
      id: 'cid'
   }
}

Now I want to change it as

{
   name: 'my name',
   no:12345,
   course : {
      name: 'cname1',
      id: 'cid1'
   },
   fees: {
      primaryFee: 1000,
      donation: 100,
   }
}

Or even delete the course key with it's value.

One way I thought of to achieve this is read the entire file and store it in a variable(json parsed). And update the value in that variable and write the whole data to the file.

But this is not efficient as it reads and writes the whole data every time of an update.

So is there any efficient approach for this to update or delete a particular key in the file itself???

Answer 1

Since you are working on a file based data store, you could use FS in node.js to read and write files. The readfilesync callback returns you the whole content of the file which should be parsed as JSON and changes are to be made.

So AFAIK the only solution is to read the whole file and then update or delete the value. In the worst case scenario you will traverse O(n) when you are trying to update or deleting the key.