I am trying to extract the first line of a file using npm firstline (https://www.npmjs.com/package/firstline) package using the following line of code
const firstline = require("firstline");
console.log("First line of the file: " + firstline("home/assets/sample.txt");
however it returns First line of the file: [object Promise]
as output.
content of file "home/assets/sample.txt" is as follows
abc
def
ghi
Therefore, I expect "abc" as output. what I am missing?
Promises in javascript need to be resolved
to get the value out of them:
const firstline = require("firstline");
firstline("home/assets/sample.txt").then(line => {
console.log("First line of the file: " + line);
});
As shown above you can use .then
or await
to get the value out.
Example using await
:
const firstline = require("firstline");
const main = async () => {
const line = await firstline("home/assets/sample.txt");
console.log("First line of the file: " + line);
};
main();
note that await need to be in an
async
function to work, otherwhise you will have a javascript syntax error