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Timer

0 likes • Feb 5, 2021
JavaScript
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Heroku Production Build

JoeCamRoberon
0 likes • Mar 11, 2021
JavaScript
if (process.env.NODE_ENV === "production") {
app.use(express.static("client/build"));
app.get("*", (req, res) => {
res.sendFile(path.resolve(__dirname, "client", "build", "index.html"));
});
}

native data structures

CodeCatch
0 likes • Nov 19, 2022
JavaScript
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

linked list

CodeCatch
0 likes • Nov 19, 2022
JavaScript
class LinkedList {
constructor() {
this.nodes = [];
}
get size() {
return this.nodes.length;
}
get head() {
return this.size ? this.nodes[0] : null;
}
get tail() {
return this.size ? this.nodes[this.size - 1] : null;
}
insertAt(index, value) {
const previousNode = this.nodes[index - 1] || null;
const nextNode = this.nodes[index] || null;
const node = { value, next: nextNode };
if (previousNode) previousNode.next = node;
this.nodes.splice(index, 0, node);
}
insertFirst(value) {
this.insertAt(0, value);
}
insertLast(value) {
this.insertAt(this.size, value);
}
getAt(index) {
return this.nodes[index];
}
removeAt(index) {
const previousNode = this.nodes[index - 1];
const nextNode = this.nodes[index + 1] || null;
if (previousNode) previousNode.next = nextNode;
return this.nodes.splice(index, 1);
}
clear() {
this.nodes = [];
}
reverse() {
this.nodes = this.nodes.reduce(
(acc, { value }) => [{ value, next: acc[0] || null }, ...acc],
[]
);
}
*[Symbol.iterator]() {
yield* this.nodes;
}
}
const list = new LinkedList();
list.insertFirst(1);
list.insertFirst(2);
list.insertFirst(3);
list.insertLast(4);
list.insertAt(3, 5);
list.size; // 5
list.head.value; // 3
list.head.next.value; // 2
list.tail.value; // 4
[...list.map(e => e.value)]; // [3, 2, 1, 5, 4]
list.removeAt(1); // 2
list.getAt(1).value; // 1
list.head.next.value; // 1
[...list.map(e => e.value)]; // [3, 1, 5, 4]
list.reverse();
[...list.map(e => e.value)]; // [4, 5, 1, 3]
list.clear();
list.size; // 0

kNearestNeighbors

CodeCatch
0 likes • Nov 19, 2022
JavaScript
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

stripe api json iteration

AustinLeath
0 likes • Nov 18, 2022
JavaScript
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;
}, []);

URL Search Term Generator

JoeCamRoberon
0 likes • Jan 17, 2021
JavaScript
const getSearchTerm = delimiter => {
let searchTerm = "";
for (let i = 1; i < commands.length - 1; i++)
searchTerm = searchTerm + commands[i] + delimiter;
searchTerm += commands[commands.length - 1];
return searchTerm;
};