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Redux Slice

1 like • Mar 11, 2021
JavaScript
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Express Login Endpoint

JoeCamRoberon
0 likes • Mar 11, 2021
JavaScript
router.post("/", async (req, res) => {
const { email, password } = req.body;
try {
if (!email) return res.status(400).json({ msg: "An email is required" });
if (!password)
return res.status(400).json({ msg: "A password is required" });
const user = await User.findOne({ email }).select("_id password");
if (!user) return res.status(400).json({ msg: "Invalid credentials" });
const match = await bcrypt.compare(password, user.password);
if (!match) return res.status(400).json({ msg: "Invalid credentials" });
const accessToken = genAccessToken({ id: user._id });
const refreshToken = genRefreshToken({ id: user._id });
res.cookie("token", refreshToken, {
expires: new Date(Date.now() + 604800),
httpOnly: true,
});
res.json({ accessToken });
} catch (err) {
console.log(err.message);
res.status(500).json({ msg: "Error logging in user" });
}
});

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]

find primes

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const primes = num => {
let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2),
sqroot = Math.floor(Math.sqrt(num)),
numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2);
numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y === x)));
return arr;
};
primes(10); // [2, 3, 5, 7]

Flatten an array

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));
// Or
const flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);
// Or
// See the browser compatibility at https://caniuse.com/#feat=array-flat
const flat = arr => arr.flat();
// Example
flat(['cat', ['lion', 'tiger']]); // ['cat', 'lion', 'tiger']

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

Convert data to yyyy mm dd format

CodeCatch
0 likes • Nov 19, 2022
JavaScript
// `date` is a `Date` object
const formatYmd = date => date.toISOString().slice(0, 10);
// Example
formatYmd(new Date()); // 2020-05-06