noam1610/training-js-algo

Training js repo

This repo is aimed at providing some algorithmic and js examples in order to improve my code.

Algorithmic skills

Javascript

Array

[link for MDN] : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype?v=example

forEach

Go through an array and return the value

listTest = [1,2,3];
listTest.forEach(function(item) {
    console.log(item)
})

slice

slice is used to extract a sub-array from an array.
The first argument is the first position to start from, it is included in the sub-array.
The first argument is the second position to stop at, it is not included in the sub-array.

var array = ['A','B','C','D'];
console.log('array.slice(2,3)', array.slice(2,3))
//['C']

If there is no argument, it will duplicate the array

var array = ['A','B','C','D'];
console.log('array.slice()', array.slice())
//['A','B','C','D']

splice

slice is used to add or remove into an array.
The first argument is the first position to start from, it is included in the sub-array.
The second argument is the number of elements to remove

pop

Remove last element of an array

var myFish = ['angel', 'clown', 'mandarin', 'sturgeon'];
var popped = myFish.pop();
console.log(myFish); // ['angel', 'clown', 'mandarin' ] 
console.log(popped); // 'sturgeon'

copyWithin

The copyWithin() method shallow copies part of an array to another location in the same array and returns it, without modifying its size. arr.copyWithin(target, start, end) target index at which to copy start index at which to start copying elements from end index at which to end copying elements from

[1, 2, 3, 4, 5].copyWithin(-2);
// [1, 2, 3, 1, 2]

[1, 2, 3, 4, 5].copyWithin(0, 3);
// [4, 5, 3, 4, 5]

[1, 2, 3, 4, 5].copyWithin(0, 3, 4);
// [4, 2, 3, 4, 5]

reverse

Reverse the order of an array

var a = ['one', 'two', 'three'];
a.reverse(); 
console.log(a); // ['three', 'two', 'one']

shift

The shift() method removes the first element from an array and returns that element. This method changes the length of the array.

var a = [1, 2, 3];
var b = a.shift();

console.log(a); // [2, 3]
console.log(b); // 1

sort

The sort() method sorts the elements of an array in place and returns the array. The sort is not necessarily stable. The default sort order is according to string Unicode code points.

var scores = [1, 10, 21, 2]; 
scores.sort(); // [1, 10, 2, 21]

var items = [
    { name: 'Edward', value: 21 },
    { name: 'Sharpe', value: 37 },
    { name: 'And', value: 45 },
    { name: 'The', value: -12 },
    { name: 'Magnetic', value: 13 },
    { name: 'Zeros', value: 37 }
];


items.sort(function(a, b) {
    return a.value - b.value;
});

console.log(items)