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An array is a data structure that contains a list of elements which store multiple values under a single variable.
let ListItems=; ListItems=['shoes','watch','bag'];
myArray = Date.now; myArray = myFunction; myArray = myItems;
The purpose of using an array is to store multiple values in a single entity of a declared variable. Arrays are used when we want to access elements in an orderly fashion using a single variable. One can store strings, boolean and numbers in a single array.
push() – It is easy to remove elements and add new elements while working with arrays. The push() method adds a new element to the end of an array. The return value is the new array length.
let listItems = ['bag','shoes','dress']; console.log(listItems.push('watch'));
Push() doest not return the value that has been added to the array. It only returns the new length of the array.
pop() – The pop() method is used to remove the last element from an array. It returns the value that has been popped out.
let listItems = ['bag','shoes','dress']; console.log(listItems.pop());
Pop() returns the value that has been removed and not the array length like Push().
shift() – Shifting is similar to popping, working on the first element instead of the last. The shift() method is used to remove the first array element and shifts all other elements to a lower index. It will return you the string that has been shifted out.
let listItems = ['bag','shoes','dress']; console.log(listItems.shift());
Shift() works same as pop() but it returns the first element of the array instead of the last one.
unshift() – The unshift() method adds a new element at the beginning of an array and unshifts older elements. It is similar to Push() and returns the new array length.
let listItems = ['bag','shoes','dress','watch']; console.log(listItems.unshift('phone'));
Unshift() will add the new element into the array and return the length of the new array.
concat() – The concat() method creates a new array by concatenating or merging existing arrays. It does not modify the existing array and always returns a new array.
let arr1 = ['red','blue','green']; let arr2 = ['colors','spraypaint', 'brush']; let newArr = arr1.concat(arr2); console.log(newArr);
toString() – The toString() method is used to convert an array to a string of array values, separated by commas.
let colors = ['red','blue','green']; console.log(colors.toString());
join() – The join() method works same as toString(). It is used to join all array elements into a string, but in addition, you can specify the separator.
let colors = ['red','blue','green']; console.log(colors.join("+"));
reverse() – The reverse() method is used to reverse the order of the elements in an array. It will change the original array and swap the order of the elements.
let fruits = ['mango','apple','grapes']; console.log(fruits.reverse());
sort() – The sort() method is used to sort an array alphabetically. This function sorts the values as string by default.
let fruits = ['mango','apple','grapes']; console.log(fruits.sort());
slice() – The slice() method is used to slice out a piece of an array into a new array. It creates a new array without removing any elements from the source array. It will return the value that has been sliced out from the array.
let colors = ['red','blue','green','yellow','orange']; console.log(colors.slice(1,3));