How to compare user input with string getting from process.stdin.on()?

Shovon Das 0
Viewed 25

When I'm trying to compare a string with an input from process.stdin.on , I'm getting false always.

//Imagine user inputting 'hello' always.

process.stdin.on('data', userInput => {
  let text = userInput.toString();
  if(text == 'hello'){
    console.log("True");
  }
  if(text === 'hello'){
    console.log("True");
  }
  process.exit();
});

If I check typeof userInput it shows string. If i log userInput it shows exact the same as my string.

so, why these conditions are false?

console node.js javascript
2 Answers

The user input includes the end-of-line markers, for example "\r\n" in Windows (but this might be "\n" on other systems). So you must check whether text === "hello\r\n".

Alternatively, you can let readline split the user input into lines for you:

readline.createInterface({input: process.stdin})
.on("line", text => {
  if(text === 'hello')
    console.log("True");
});
Heiko Theißen0

Another alternative , you could use openStdin with a listener

const stdin = process.openStdin();
stdin.addListener("data", function(d) {
    const text = d.toString().trim();
    console.log("you entered: [" + d.toString().trim() + "]");
    if (text == 'hello') {
        console.log("True");
    }
    if (text === 'hello') {
        console.log("True");
    }
});
Taha Azzabi0
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