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Zybooks?

0 likes • Oct 29, 2020
JavaScript
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quick sort

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const quickSort = arr => {
const a = [...arr];
if (a.length < 2) return a;
const pivotIndex = Math.floor(arr.length / 2);
const pivot = a[pivotIndex];
const [lo, hi] = a.reduce(
(acc, val, i) => {
if (val < pivot || (val === pivot && i != pivotIndex)) {
acc[0].push(val);
} else if (val > pivot) {
acc[1].push(val);
}
return acc;
},
[[], []]
);
return [...quickSort(lo), pivot, ...quickSort(hi)];
};
quickSort([1, 6, 1, 5, 3, 2, 1, 4]); // [1, 1, 1, 2, 3, 4, 5, 6]

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);
}
});

Get timezone as a string

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const getTimezone = () => Intl.DateTimeFormat().resolvedOptions().timeZone;
// Example
getTimezone();

insertion sort

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const insertionSort = arr =>
arr.reduce((acc, x) => {
if (!acc.length) return [x];
acc.some((y, j) => {
if (x <= y) {
acc.splice(j, 0, x);
return true;
}
if (x > y && j === acc.length - 1) {
acc.splice(j + 1, 0, x);
return true;
}
return false;
});
return acc;
}, []);
insertionSort([6, 3, 4, 1]); // [1, 3, 4, 6]

permutations

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const permutations = arr => {
if (arr.length <= 2) return arr.length === 2 ? [arr, [arr[1], arr[0]]] : arr;
return arr.reduce(
(acc, item, i) =>
acc.concat(
permutations([...arr.slice(0, i), ...arr.slice(i + 1)]).map(val => [
item,
...val,
])
),
[]
);
};
permutations([1, 33, 5]);
// [ [1, 33, 5], [1, 5, 33], [33, 1, 5], [33, 5, 1], [5, 1, 33], [5, 33, 1] ]

Destructuring Assignment

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: ');
//using destructuring assignment
[a, b] = [b, a];
console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);