08 Nov 2020
In a simple term, an array is a collection of items that consist of the same datatype. It usually have at least one item in the collection and it's starting index is always 0.
Let's create our first array
let food = ['Rice','Bread','Meat']
We have created an array and stored it in a variable.
We can retrieve an item from an array by specifying the index.
let first = food[0]
console.log(first)
// Rice
The push()
method add a new item to an array.
let updatedFood = food.push('Beans')
console.log(updatedFood)
// ['Rice','Bread','Meat','Beans']
The pop()
method remove an item from an array
let updatedFood = food.pop()
console.log(updatedFood)
// ['Rice','Bread']
The includes()
method checks if an item is in the array(usually return a boolean value)
let checkFood = food.includes('Bread')
console.log(checkFood)
// true
The indexOf()
method search for an item in the array and returns the position is found else it returns -1
let foodPosition = food.indexOf('Rice')
console.log(foodPosition)
// 0
The map()
method returns a new array with a result of calling a function on every item of the array
let numbers = ['1','2','3']
function addToNumber(num){
return num + 2;
}
let newArray = numbers.map(addToNumber)
console.log(newArray)
// ['2','4','6']
The slice()
method extracts items from an array based on passed in arguments or else it will copy the array. This method can take two arguments, the first argument is the starting position of the item you want to extract while the second argument is the ending position. It returns a new array with of result with the passed in argument and the arguments.
let extractedFood = food.slice(1,2)
console.log(extractedFood)
// ['Beans','Meat']
The filter()
method returns a new array containing all items of the calling array for which the provided filtering function returns true
.
let result = food.filter(word => word.length > 4);
console.log(result);
// ["Bread", "Meat"]
The toString()
method converts an array to a sting
let foodString = food.toString()
console.log(foodString)
// Rice,Bread,Meat
The sort()
method returns a sorted array
let sortedFood = food.sort()
console.log(sortedFood)
// ['Bread','Meat','Rice']
Hope it helped.
Thanks