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Subsets of an array

Nov 19, 2022CodeCatch
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Get union of arrays

Nov 19, 2022CodeCatch

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const union = (...arr) => [...new Set(arr.flat())];
// Example
union([1, 2], [2, 3], [3]); // [1, 2, 3]

stripe api json iteration

Nov 18, 2022AustinLeath

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var arr = [{
"success": true,
"data": [
{
"id": "ipi_1KrrbvDOiB2klwsKhuqUWqt1",
"object": "issuing.transaction",
"amount": -2743,
"amount_details": {
"atm_fee": null
},
"authorization": "iauth_1KrrbuDOiB2klwsKoFjQZhhd",
"balance_transaction": "txn_1KrrbwDOiB2klwsK1YkjJJRi",
"card": "ic_1Krqe5DOiB2klwsK44a35eiE",
"cardholder": "ich_1KrqL8DOiB2klwsKtBnZhzYr",
"created": 1650753567,
"currency": "usd",
"dispute": null,
"livemode": false,
"merchant_amount": -2743,
"merchant_currency": "usd",
"merchant_data": {
"category": "advertising_services",
"category_code": "7311",
"city": "San Francisco",
"country": "US",
"name": "Aeros Marketing, LLC",
"network_id": "1234567890",
"postal_code": "94103",
"state": "CA"
},
"metadata": {},
"type": "capture",
"wallet": null
},
{
"id": "ipi_1Krrbvc62B2klwsKhuqUWqt1",
"object": "issuing.transaction",
"amount": -9999,
"amount_details": {
"atm_fee": null
},
"authorization": "iauth_1KrrbuDOiB2klwsKoFjQZhhd",
"balance_transaction": "txn_1KrrbwDOiB2klwsK1YkjJJRi",
"card": "ic_1Krqe5DOiB2klwsK44a35eiE",
"cardholder": "ich_1KrqL8DOiB2klwsKtBnZhzYr",
"created": 1650753567,
"currency": "USD",
"dispute": null,
"livemode": false,
"merchant_amount": -9999,
"merchant_currency": "usd",
"merchant_data": {
"category": "fast_food",
"category_code": "7311",
"city": "San Francisco",
"country": "US",
"name": "Aeros Marketing, LLC",
"network_id": "1234567890",
"postal_code": "94103",
"state": "CA"
},
"metadata": {},
"type": "capture",
"wallet": null
}
]
}];
const reduced = arr.reduce((prev, curr) => {
prev.push({
amount: curr.data[0].merchant_amount,
id: curr.data[0].id,
currency: curr.data[0].currency,
category: curr.data[0].merchant_data.category
});
console.log(prev)
return prev;
}, []);

Temperature Converter

Nov 19, 2022CodeCatch

0 likes • 2 views

const celsiusToFahrenheit = (celsius) => celsius * 9/5 + 32;
const fahrenheitToCelsius = (fahrenheit) => (fahrenheit - 32) * 5/9;
// Examples
celsiusToFahrenheit(15); // 59
celsiusToFahrenheit(0); // 32
celsiusToFahrenheit(-20); // -4
fahrenheitToCelsius(59); // 15
fahrenheitToCelsius(32); // 0

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

Function promisification

Nov 19, 2022CodeCatch

0 likes • 0 views

// 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 => ...);

Untitled

Apr 14, 2023Helper

0 likes • 8 views

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)];
};
console.log(quickSort([1, 6, 1, 5, 3, 2, 1, 4])) // [1, 1, 1, 2, 3, 4, 5, 6]