Skip to main content

Express Login Endpoint

0 likes • Mar 11, 2021
JavaScript
Loading...
Download

More JavaScript Posts

drag and drop uploader

AustinLeath
0 likes • Nov 18, 2022
JavaScript
const dragAndDropDiv = editor.container;
dragAndDropDiv.addEventListener('dragover', function(e) {
e.stopPropagation();
e.preventDefault();
e.dataTransfer.dropEffect = 'copy';
});
dragAndDropDiv.addEventListener("drop",function(e){
// Prevent default behavior (Prevent file from being opened)
e.stopPropagation();
e.preventDefault();
const files = e.dataTransfer.items; // Array of all files
console.assert(files.length >= 1);
if (files[0].kind === 'file') {
var file = e.dataTransfer.items[0].getAsFile();
const fileSize = file.size;
const fileName = file.name;
const fileMimeType = file.type;
reader = new FileReader();
reader.onloadend = function(){
editor.setValue(reader.result);
}
reader.readAsText(file);
}else{
//Maybe handle if text is dropped
console.log(files[0].kind);
}
});

K-means clustering

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const kMeans = (data, k = 1) => {
const centroids = data.slice(0, k);
const distances = Array.from({ length: data.length }, () =>
Array.from({ length: k }, () => 0)
);
const classes = Array.from({ length: data.length }, () => -1);
let itr = true;
while (itr) {
itr = false;
for (let d in data) {
for (let c = 0; c < k; c++) {
distances[d][c] = Math.hypot(
...Object.keys(data[0]).map(key => data[d][key] - centroids[c][key])
);
}
const m = distances[d].indexOf(Math.min(...distances[d]));
if (classes[d] !== m) itr = true;
classes[d] = m;
}
for (let c = 0; c < k; c++) {
centroids[c] = Array.from({ length: data[0].length }, () => 0);
const size = data.reduce((acc, _, d) => {
if (classes[d] === c) {
acc++;
for (let i in data[0]) centroids[c][i] += data[d][i];
}
return acc;
}, 0);
for (let i in data[0]) {
centroids[c][i] = parseFloat(Number(centroids[c][i] / size).toFixed(2));
}
}
}
return classes;
};
kMeans([[0, 0], [0, 1], [1, 3], [2, 0]], 2); // [0, 1, 1, 0]

arithmetic progression

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const arithmeticProgression = (n, lim) =>
Array.from({ length: Math.ceil(lim / n) }, (_, i) => (i + 1) * n );
arithmeticProgression(5, 25); // [5, 10, 15, 20, 25]

Function promisification

CodeCatch
0 likes • Nov 19, 2022
JavaScript
// promisify(f, true) to get array of results
function promisify(f, manyArgs = false) {
return function (...args) {
return new Promise((resolve, reject) => {
function callback(err, ...results) { // our custom callback for f
if (err) {
reject(err);
} else {
// resolve with all callback results if manyArgs is specified
resolve(manyArgs ? results : results[0]);
}
}
args.push(callback);
f.call(this, ...args);
});
};
}
// usage:
f = promisify(f, true);
f(...).then(arrayOfResults => ..., err => ...);

Date Time Testing

AustinLeath
0 likes • Nov 18, 2022
JavaScript
var d = new Date();
var d = new Date(milliseconds);
var d = new Date(dateString);
var d = new Date(year, month, day, hours, minutes, seconds, milliseconds);

Bitwise XOR operator

CodeCatch
0 likes • Nov 19, 2022
JavaScript
//JavaScript program to swap two variables
//take input from the users
let a = prompt('Enter the first variable: ');
let b = prompt('Enter the second variable: ');
// XOR operator
a = a ^ b
b = a ^ b
a = a ^ b
console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);