I am trying to store the data read by fs in a variable. But I am getting undefined as output.
const fs = require("fs");
var a;
fs.readFile("analogData.txt", "utf8", (err, data) => {
a = data;
});
console.log(a);
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Ravi Shah
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Does this answer your question? [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) – Robin Zigmond Apr 24 '21 at 11:04
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const fs = require("fs");
let a;
fs.readFile("analogData.txt", "utf8", (err, data) => {
a = data;
console.log(a);
});
You might have not created the text file. SO, create it and run the program again.
CodeWebProjects
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const fs = require("fs"); let a; fs.readFile("analogData.txt", "utf8", (err, data) => { a = data; console.log(a); }); console.log(a) The last console.log is showing undefined – Ravi Shah Apr 24 '21 at 12:13
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If a put console.log(a) inside in the scope then I will get the correct value but I need the value outside the scope. – Ravi Shah Apr 26 '21 at 07:10
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For console.log outside of the callback function, it always gives undefined. Since it executes before "a" variable being set in the callback. Callback function runs after console.log.
Mumin Korcan
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