array-methods.txt

const arr = [1, 3, 5, 7];
const users = [
	{ name: 'grace', city: 'Manchester', age: 30 },
	{ name: 'monica', city: 'Liverpool', age: 24 },
];
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keys() - Example

const iterator = arr.keys();
for (const key of iterator) {
console.log(key);
}

Result - 
0
1 
2 
3
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values() - Example

const iterator = arr.values();
for (const value of iterator) {
console.log(value);
}

Result - 
1
3
5 
7
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push() - Example 

console.log(arr.push(9));
console.log(arr);

Result -  5 - new length of the array
[1, 3, 5, 7, 9]
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pop() - Example

console.log(arr.pop());
console.log(arr);

Result - 7 // last element of the array
[1, 3, 5]
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slice() - Example

console.log(arr.slice(1, 3));
console.log(arr);
// remain from index 1 to 2 (last one is not included)


Result - 6 // new length of the array
[2, 4, 1, 3, 5, 7]
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splice() - Example 

arr.splice(1, 0, 2); // insert ‘2’ at index 1
console.log(arr);

Result - [1, 2, 3, 5, 7]

Example 2 - 

arr.splice(3, 1, 4); // replace 1 item at index 3
console.log(arr);

Result 2 - [1, 3, 5, 4]
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Reduce() - Example

console.log(arr.reduce((pre, curr) => pre + curr));

Result - 16
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find() - Example

console.log(arr.find((num) => num > 3));

Result - 5
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filter() - Example 

console.log(arr.filter((num) => num > 3));
const newUsers = users.filter((user) => user.age > 25);
console.log(newUsers);

Result - [5, 7]
[ { name: 'grace', city: 'Manchester', age: 30 } ]
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map() - Example

arr.map((item) => item * 2)
users.map((user) => console.log(user.name));

Result - [2, 6, 10, 14]
grace
monica
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forEach() - Example

arr.forEach((item) => console.log(item * 2));

Result - 
2
6
10
14
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includes() - Example

console.log(arr.includes(3));

Result - True
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