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Midhun
Midhun

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9 Useful JavaScript Array Tips and Tricks You Should Know

There are several very basic tips about Javascript arrays that will help you improve your Javascript skills. Now let's do a little coding...

1.Reverse an Array

let name = ['Mike', 'Matt', 'Nancy', 'Adam', 'Jenny', 'Carl']
reversed = [...name].reverse()]
console.log(reversed)
['Carl', 'Jenny', 'Adam', 'Nancy', 'Matt', 'Mike']
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2.Sort Array

var names = ["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"];
uniq = [...new Set(names)];
console.log(uniq)
['Mike', 'Matt', 'Nancy', 'Adam', 'Jenny', 'Carl']

//method 2

let uniqueArray = names.filter(function(item, pos) {
    return names.indexOf(item) == pos;
})

console.log(uniqueArray)

['Mike', 'Matt', 'Nancy', 'Adam', 'Jenny', 'Carl']
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3.Get random value

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.sort();


//Method 2 
let a =[ { firstName: 'John', age: 27 }, { firstName: 'Ana', age: 25 }, { firstName: 'Zion', age: 30 } ];

a.sort((a, b) => {
    return a.age - b.age;
});



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4.Intersection,Union,Difference of two arrays

arrA=[1,3,4,5]
arrB=[1,2,5,6,7]
let intersection = arrA.filter(x => arrB.includes(x));
console.log(intersection)
[1, 5]
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Union

let union = [new Set([...arrA, ...arrB])]
console.log(Array.from(union[0]));
[1, 3, 4, 5, 2, 6, 7]
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Difference

let difference = arrA.filter(x => !arrB.includes(x));
console.log(difference);
[3, 4]
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5.Merge Arrays

let fruits = ['banana','mango','apple']
let veggies = ['tomato','potato','onion']
let food = [...fruits,...veggies]
console.log(food)
['banana', 'mango', 'apple', 'tomato', 'potato', 'onion']
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6.Fill array with data

var newArray = new Array(10).fill('data');
console.log(newArray)
['data', 'data', 'data', 'data', 'data', 'data', 'data', 'data', 'data', 'data']

//Method 2

var newArray = Array.from(Array(10), () => 0 );
console.log(filledArray)
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
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7.Empty an array

food =['banana', 'mango', 'apple', 'tomato', 'potato', 'onion']

//Method 1
food.length=0

//Method 2
food = [];

//Method 3

while (food.length) { food.pop(); }

console.log(food)
[]
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8.Get random value

var items = [25, 45, 21, 65, 43];
v=items[Math.floor(Math.random()*items.length)];
console.log(v)
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9.Convert array to an object

var arr = ["One", "Two", 3];
var obj = {...arr};
console.log(obj);
{0: 'One', 1: 'Two', 2: 3}

//second way

Object.assign({}, ['a','b','c']);
console.log(obj);
{0: 'a', 1: 'b', 2: 'c'}
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