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Jude Eigbiremonlen
Jude Eigbiremonlen

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Get Started with CSVParse for Node.js (csv-parse npm package)

#node #javascript #data #tutorial

The csv-parse is a parsing package that interprets CSV input into array or object. It uses Nodejs stream API under the hood but has been optimised for easy of use and parsing large datasets.

Usage

To get started run the following command to install the package in your existing or new project.
Install the package

npm i csv-parse
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Example CSV (data.csv)

name,age,email
Alex,33,alex@example.com 
Bekky,20,bekky@example.com 
Carl,27,carl@example.com
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Read and Parse data.csv 

import fs from 'node:fs';
import {parse} from 'csv-parse';

const records =[];

fs.createReadStream('path/data.csv')
.pipe(
   parse{
     columns: true, //use first row as header
     skip_empty_lines: true,
   }
)
.on('data',(row)=>{
   records.push(row);
})
.on('error',(err)=>{
   console.error(err.message);
})
.on('end', ()=>{
    console.log(records);
});
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Output 

[
  { name: 'Alex', age: '33', email: 'alex@example.com' },
  { name: 'Bekky', age: '20', email: 'bekky@example.com' },
  { name: 'Carl', age: '27', email: 'carl@example.com' }
]
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Here's what you should always remember,

The parse API parse('input',options,callback) accepts an input which, it then interprets into structured data using the specified parsing rules passed as the options argument.

input : string or buffer
options: parsing rule (optional). e.g {columns:true/false,delimiter:","}
callback(err, records)

It is recommended you use fs.createReadStream() to stream your file piece by piece, instead of loading everything once into memory when using fs.readFile().
Stream tells node to read chunks of the file and each chunk is parsed imediately which keeps memory usage low. You can use fs.readFile() for file that is ≤ 5MB.

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