Methods

Method and object

A method is basically a function that is associated with an object. It always comes along with parenthesis, for example:

console.log(s.toUpperCase());

Simple Methods

toUpperCase

Convert a string into upper cases

const s = 'Hello World';

console.log(s.toUpperCase());

toLowerCase

Convert a string a lower cases

substring

Get part from a string. Define parameters to specify the starting and the ending positions.

const s = 'Hello World!'
console.log(s.substring(0, 5));

split

Split a string to several parts.

The following example doesn’t really define the parameter. By default, the string is splitted into letters.

const s = 'Hello World!'
console.log(s.split(''));

Handy use case: Convert a tag list into an array:

const = `technology, computers, it, code`
// Imposes splits when a comma is detected
console.log(tags.split(', '))

push

Add a value to an array.

const fruits = ['apples', 'oranges', 'pears'];
fruits.push('mangos')
console.log(fruits);

This operation works better than the working on const alone since you don’t have to necessarily figure out the count of elements within the target array.

unshift

Add a value to the beginning of an array.

const fruits = ['apples', 'oranges', 'pears'];
fruits.unshift('strawberries')
console.log(fruits);

pop

Take the last one off an array.

fruits.pop();

isArray

Check to see if something is an array.

console.log(array.isArray(fruits));

indexOf

Check out the index of an elements within the array.

console.log(fruits.indexOf('oranges'));

Method: JSON.stringify()

The JSON.stringify() method converts a JavaScript object or value to a JSON string, optionally replacing values if a replacer function is specified or optionally including only the specified properties if a replacer array is specified.

Nesting Methods

const s = 'Hello World!'
console.log(s.substring(0, 5).toUpperCase());