How To Convert CSV to JSON file Having Comma Separated Values In NodeJS?

To convert a CSV file into a JSON file in Node.js with comma-separated values, follow a structured approach that utilizes the fs module to read the file and process the data manually. Here's how you can achieve the solution

Approach

• Read the CSV file using the default fs npm package.
• Convert the data to String and split it in an array.
• Generate a headers array.
• For all the remaining n-1 rows do the following: 
  
  • Create an empty object to add values of the current row to it.
  • Declare a string str as the current array value to change the delimiter and store the generated string in a new string s.
  • If we encounter an opening quote (") then we keep commas as it is otherwise we replace them with pipe "|"
  • Keep adding the characters we traverse to a String s.
  • Split the string using pipe delimiter | and store the values in a properties array.
  • For each header, if the value contains multiple comma-separated data, then we store it in the form of an array otherwise directly the value is stored.
  • Add the generated object to our result array.

Example:

Convert the resultant array to JSON and generate the JSON output file.

//app.js/

const fs = require("fs");
csv = fs.readFileSync("CSV_file.csv")

const array = csv.toString().split("\r");
let result = [];

let headers = array[0].split(", ")

for (let i = 1; i < array.length - 1; i++) {
    let obj = {}

    let str = array[i]
    let s = ''

    let flag = 0
    for (let ch of str) {
        if (ch === '"' && flag === 0) {
            flag = 1
        }
        else if (ch === '"' && flag == 1) flag = 0
        if (ch === ', ' && flag === 0) ch = '|'
        if (ch !== '"') s += ch
    }

    let properties = s.split("|")

    for (let j in headers) {
        if (properties[j].includes(", ")) {
            obj[headers[j]] = properties[j]
                .split(", ").map(item => item.trim())
        }
        else obj[headers[j]] = properties[j]
    }
    result.push(obj)
}

let json = JSON.stringify(result);
fs.writeFileSync('output.json', json);

Explanation: This code reads a CSV file using Node.js’s fs module and converts it to a JSON format. It starts by reading the file and splitting it into an array of rows. The first row, which contains the headers, is separated and used as keys for the JSON objects. Each subsequent row is processed by handling quotes and commas properly, creating an object for each row, and adding it to a result array. Finally, the result array is converted into a JSON string and saved to a file.

Output: