Javascript: how to parse base64 encoded csv to fetch the filename and actual csv content

Question

I have a base64 string created by encoding a csv file,

const base64 = 'LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLTExNDc2MDgwNjM5MTM4ODk4MTc2NTYwNA0KQ29udGVudC1EaXNwb3NpdGlvbjogZm9ybS1kYXRhOyBuYW1lPSJmaWxlIjsgZmlsZW5hbWU9ImNoYXJ0T2ZBY2NvdW50LmNzdiINCkNvbnRlbnQtVHlwZTogdGV4dC9jc3YNCg0K77u/QWNjb3VudE51bWJlcixBY2NvdW50TmFtZSxEZWR1Y3RhYmlsaXR5DQoxMTExLHRlZWUsMTAwDQoyMjIyMix0ZXN0LDEwMA0KLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLTExNDc2MDgwNjM5MTM4ODk4MTc2NTYwNC0tDQo='

I want to get the name of the file and create the same file back with the filename. What I need to use. I am using node.js here.

Habebit · Answer 1 · 2021-08-17T18:41:04.320

If I understand your question right, your base64 variable needs to be decoded. buffer can do this:

const base64 = 'LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLTExNDc2MDgwNjM5MTM4ODk4MTc2NTYwNA0KQ29udGVudC1EaXNwb3NpdGlvbjogZm9ybS1kYXRhOyBuYW1lPSJmaWxlIjsgZmlsZW5hbWU9ImNoYXJ0T2ZBY2NvdW50LmNzdiINCkNvbnRlbnQtVHlwZTogdGV4dC9jc3YNCg0K77u/QWNjb3VudE51bWJlcixBY2NvdW50TmFtZSxEZWR1Y3RhYmlsaXR5DQoxMTExLHRlZWUsMTAwDQoyMjIyMix0ZXN0LDEwMA0KLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLTExNDc2MDgwNjM5MTM4ODk4MTc2NTYwNC0tDQo=';
// decode base64
const decodedBase64String = Buffer.from(base64, 'base64').toString();

const filename = decodedBase64String.match(/filename="(.*).csv/)[1];

console.log(decodedBase64String);

With a some regex you can extract your filename ("chartOfAccount.csv") from decodedBase64String. And then use fs (explained here) to create from your content a file.

Javascript: how to parse base64 encoded csv to fetch the filename and actual csv content

1 Answers1