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URL Search Term Generator

Jan 17, 2021C S
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array shuffle

Nov 19, 2022CodeCatch

0 likes • 0 views

const shuffle = ([...arr]) => {
let m = arr.length;
while (m) {
const i = Math.floor(Math.random() * m--);
[arr[m], arr[i]] = [arr[i], arr[m]];
}
return arr;
};
const foo = [1, 2, 3];
shuffle(foo); // [2, 3, 1], foo = [1, 2, 3]

kNearestNeighbors

Nov 19, 2022CodeCatch

0 likes • 6 views

const kNearestNeighbors = (data, labels, point, k = 3) => {
const kNearest = data
.map((el, i) => ({
dist: Math.hypot(...Object.keys(el).map(key => point[key] - el[key])),
label: labels[i]
}))
.sort((a, b) => a.dist - b.dist)
.slice(0, k);
return kNearest.reduce(
(acc, { label }, i) => {
acc.classCounts[label] =
Object.keys(acc.classCounts).indexOf(label) !== -1
? acc.classCounts[label] + 1
: 1;
if (acc.classCounts[label] > acc.topClassCount) {
acc.topClassCount = acc.classCounts[label];
acc.topClass = label;
}
return acc;
},
{
classCounts: {},
topClass: kNearest[0].label,
topClassCount: 0
}
).topClass;
};
const data = [[0, 0], [0, 1], [1, 3], [2, 0]];
const labels = [0, 1, 1, 0];
kNearestNeighbors(data, labels, [1, 2], 2); // 1
kNearestNeighbors(data, labels, [1, 0], 2); // 0

localStorage Cookie Consent

Oct 9, 2023Helper

0 likes • 266 views

import React, { useState, useEffect } from 'react';
import Link from 'next/link';
export default function CookieBanner() {
// Initialize with a default value (false if not previously set in localStorage)
const [cookieConsent, setCookieConsent] = useState(() =>
localStorage.getItem('cookieConsent') === 'true' ? true : false
);
useEffect(() => {
const newCookieConsent = cookieConsent ? 'granted' : 'denied';
window.gtag('consent', 'update', {
analytics_storage: newCookieConsent
});
localStorage.setItem('cookieConsent', String(cookieConsent));
}, [cookieConsent]);
return !cookieConsent && (
<div>
<div>
<p>
We use cookies to enhance the user experience.{' '}
<Link href='/privacy/'>View privacy policy</Link>
</p>
</div>
<div>
<button type="button" onClick={() => setCookieConsent(false)}>Decline</button>
<button type="button" onClick={() => setCookieConsent(true)}>Allow</button>
</div>
</div>
)
}

native data structures

Nov 19, 2022CodeCatch

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const nums = [1, 2, 3];
const strs = Array.from('est');
nums.push(6);
nums.push(4, 9);
strs.unshift('t');
nums.length; // 6
nums[nums.length - 1]; // 9
strs[0]; // 't'
strs[2]; // 's'
nums.slice(1, 3); // [2, 3]
nums.map(n => n * 2); // [2, 4, 6, 12, 8, 18]
nums.filter(n => n % 2 === 0); // [2, 6, 4]
nums.reduce((a, n) => a + n, 0); // 25
strs.reverse(); // ['t', 's', 'e', 't']
strs.join(''); // 'test'
const nums = new Set([1, 2, 3]);
nums.add(4);
nums.add(1);
nums.add(5);
nums.add(4);
nums.size; // 5
nums.has(4); // true
nums.delete(4);
nums.has(4); // false
[...nums]; // [1, 2, 3, 5]
nums.clear();
nums.size; // 0
const items = new Map([
[1, { name: 'John' }],
[2, { name: 'Mary' }]
]);
items.set(4, { name: 'Alan' });
items.set(2, { name: 'Jeff' });
items.size; // 3
items.has(4); // true
items.get(2); // { name: 'Jeff' }
items.delete(2);
items.size; // 2
[...items.keys()]; // [1, 4]
[...items.values()]; // [{ name: 'John' }, { name: 'Alan' }]
items.clear();
items.size; // 0

LeetCode Product Except Self

Sep 13, 2023C S

0 likes • 11 views

/**
* @param {number[]} nums
* @return {number[]}
*/
var productExceptSelf = function(nums) {
var output = [];
var leftMult = 1;
var rightMult = 1;
for (var i=nums.length - 1; i >= 0; i--) {
output[i] = rightMult;
rightMult *= nums[i];
console.log({output: JSON.stringify(output), i})
}
for (var j=0; j < nums.length; j++) {
output[j] *= leftMult;
leftMult *= nums[j];
console.log({output: JSON.stringify(output), j})
}
return output;
};
console.log(productExceptSelf([1, 2, 3, 4]))

unzipWith() function

Nov 19, 2022CodeCatch

0 likes • 0 views

const unzipWith = (arr, fn) =>
arr
.reduce(
(acc, val) => (val.forEach((v, i) => acc[i].push(v)), acc),
Array.from({
length: Math.max(...arr.map(x => x.length))
}).map(x => [])
)
.map(val => fn(...val));
unzipWith(
[
[1, 10, 100],
[2, 20, 200],
],
(...args) => args.reduce((acc, v) => acc + v, 0)
);
// [3, 30, 300]