I am using the 'csv-parser' library. Using the method below I am able to get the data stored in the birthdays array shown in the console:
const birthdays = [];
fs.createReadStream('./data/groupes.csv')
.pipe(csv({}))
.on('data', (data) => birthdays.push(data))
.on('end', () => {
console.log(birthdays)
});
but when I log outside the .on('end') like below, the console shows the birthdays array as empty:
const birthdays = [];
fs.createReadStream('./data/groupes.csv')
.pipe(csv({}))
.on('data', (data) => birthdays.push(data))
.on('end', () => {
});
console.log(birthdays)
Why is that? and how can I solve it? Thanks in advance.
Why is that?
It's because createReadStream is working asynchronously and when you console.log(birthdays); outside, the code execution reads the log before createReadStream has finished processing
how can I solve it?
You were correct to put it inside the .on("end")
const birthdays = [];
fs.createReadStream('./data/groupes.csv')
.pipe(csv({}))
.on('data', (data) => birthdays.push(data))
.on('end', () => {
console.log(birthdays);
// further processing with birthdays
});
Could you do something like this?
const csv = require("csv-parser");
const fs = require("fs");
const path = require("path");
const { promisify } = require("util");
const readFile = promisify(fs.readFile);
const birthdays = [];
const filePath = path.join(__dirname, "data", "groupes.csv");
readFile(filePath, "utf8").then((data) => {
csv(data, {
separator: ",",
})
.on("data", (row) => {
birthdays.push(row);
})
.on("end", () => {
console.log(birthdays);
});
});