Manipulate values in a JSON in nodeJS [duplicate] - node.js

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How to update a value in a json file and save it through node.js
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Closed 2 years ago.
I am new to Nodejs and JSON manipulations. I have a jSON that looks like
"ent": [
{
"employee": [
{
"emp_name": "",
"column": "employee",
"emp_id": 123456,
"first name": "Joe",
"last name": "Bloggs",
"email": "",
"ldapid":
} ,
{
"emp_name": "",
"column": "employee",
"emp_id": 123456,
"first name": "Foo",
"last name": "Bars",
"email": "",
"ldapid":
}
]
}
]
I need to fill the email, ldapid and emp_name based on the firstname and last name
The desired output is
"ent": [
{
"employee": [
{
"emp_name": "Joe Bloggs",
"column": "employee",
"emp_id": 123456,
"first name": "Joe",
"last name": "Bloggs",
"email": "jbloggs#mycompemail.com",
"ldapid": "jbloggs"
} ,
{
"emp_name": "Foo Bars",
"column": "employee",
"emp_id": 567891,
"first name": "Foo",
"last name": "Bars",
"email": "fbars#mycompemail.com",
"ldapid": "fbars"
}
]
}
]
Since I am super new to the nodeJS world , I am making some initial steps to get to where I want..
The following is what I have done..
EDITED my POST
Hi All, Thanks for all your responses.
I was hoping to get an answer that did something similar to the below. this may not be a code with best practices, but does what I want, may be experts in this group can make it better.
const fs = require('fs');
/** Method to start
*
*
*/
const main = async () => {
const myJSONObject = require('./people.json');
try {
for (var i = 0; i < myJSONObject.entities.length; i++) {
var entity = myJSONObject.entities[i];
if (entity.People) {
for (var j = 0; j < entity.People.length; j++) {
var people = entity.People[j];
var fn = people["first name"];
var ln = people["last name"];
var email = `${fn.substring(0, 3)}${ln.substring(0, 5)}#mycompmail.com`;
var ldapid = `${fn.substring(0, 3)}${ln.substring(0, 5)}`;
myJSONObject.entities[i].People[j]["email"] = email.toLowerCase();
myJSONObject.entities[i].People[j]["ldap id"] = ldapid.toLowerCase();
myJSONObject.entities[i].People[j]["preferred first name"] = fn;
myJSONObject.entities[i].People[j]["preferred last name"] = ln;
// console.log(`${fn}.${ln}`)
}
}
}
fs.writeFileSync('./new_people.json', JSON.stringify(myJSONObject, 0, 4));
}
catch (error) {
console.log(error);
}
};
(async () => {
await main();
})();
Any help in this is highly appreciated.
Vakichak

Answer 1

From your code snipped I assume, that the JSON is a string in a file.
So the first step you need to do is to import the file contents into a variable. You can do that with fs.readFileSync(). Now you have the string in a variable.
Next you need to do is to convert the string into an object. You can do that with JSON.parse(). Now you have an object that you can manipulate.
To write it the object back into a file, you can use JSON.stringify() to make it a string again and then fs.writeFileSync() to write it to the file.
Full script:
const jsonString = fs.readFileSync('./people.json')
const jsonObject = JSON.parse(jsonString)
// do stuff with jsonObject that is written into newJsonObject
const newJsonString = JSON.stringify(newJsonObject)
fs.writeFileSync('./new_people.json', newJsonObject)
Note: there's also async functions for writing and reading files. The sync functions are okay if you load a config or something like this at the beginning of a script. If you read/write many files during runtime, you should use the async functions.