Check if a string starts with the value of the string passed as parameter.
You can call startsWith() on any string, provide a substring, and check if the result returns true or false:
'testing'.startsWith('test') //true
'going on testing'.startsWith('test') //false
This method accepts a second parameter, which lets you specify at which character you want to start checking:
'testing'.startsWith('test', 2) //false
'going on testing'.startsWith('test', 9) //true