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// create a node command line listener that allows the user to press any key , and averages the distances between the key presses to determine the BPM (with a window of 4 key presses). If the user presses q, the program should exit and print the final BPM.
// Import the necessary modules
import * as readline from 'readline';
export function tapBpm() {
// Set up readline interface to listen for keypresses
readline.emitKeypressEvents(process.stdin);
process.stdin.setRawMode(true);
// accept SIGINT on stdin
// Array to store the time differences between the last 4 key presses
const timeDifferences: number[] = [];
let lastPressTime: number | null = null;
// Function to calculate BPM based on average time between keypresses
function calculateBPM() {
if (timeDifferences.length < 1) {
return 0;
}
const averageTimeDiff =
timeDifferences.reduce((acc, curr) => acc + curr, 0) / timeDifferences.length;
return (60 * 1000) / averageTimeDiff;
}
// Handle the SIGINT (Ctrl+C) event manually
process.on('SIGINT', () => {
console.log('\nExiting via SIGINT (Ctrl+C)... Final BPM:', calculateBPM().toFixed(2));
process.exit();
});
// Listen for keypress events
process.stdin.on('keypress', (str, key: { name: string; sequence: string }) => {
// Exit if 'q' is pressed
if (key.name === 'q') {
console.log('Exiting... Final BPM:', calculateBPM().toFixed(2));
process.exit();
}
// Handle Ctrl+C (SIGINT)
if (key.sequence === '\u0003') {
// '\u0003' is the raw code for Ctrl+C
console.log('\nExiting via Ctrl+C... Final BPM:', calculateBPM().toFixed(2));
process.exit();
}
// Capture the current time of the keypress
const currentTime = Date.now();
// If it's not the first keypress, calculate the time difference
if (lastPressTime !== null) {
const timeDiff = currentTime - lastPressTime;
// Add the time difference to the array (limit to last 10 key presses)
if (timeDifferences.length >= 10) {
timeDifferences.shift(); // Remove the oldest time difference
}
timeDifferences.push(timeDiff);
// Calculate and display the BPM
const bpm = calculateBPM();
console.log('Current BPM:', bpm.toFixed(2));
} else {
console.log('Waiting for more key presses to calculate BPM...');
}
// Update the lastPressTime to the current time
lastPressTime = currentTime;
});
console.log('Press any key to calculate BPM, press "q" to quit.');
}
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