JS: split() vs. join()

split()

go to see the post

 

Array.prototype.join()

1. Method
2. Convert the elements of an array into a string

3. The string conversions of all array elements are joined into one string.

4. Creates and returns a new string by concatenating all of the elements in an array (or an array-like object▼).

The following example joins an array-like object (arguments), by calling Function.prototype.call on Array.prototype.join.

function f(a, b, c) {
  var s = Array.prototype.join.call(arguments);
  console.log(s); // '1,a,true'
}
f(1, 'a', true);
//expected output: "1,a,true"

5. The default separator is comma (,)

6. or a specified separator string
   : If the array has only one item, then that item will be returned without using the separator.

 

[Syntax]

arr.join([separator])

separator	optional	Specifies a string to separate each pair of adjacent elements of the array.
		The separator is converted to a string if necessary.
		If omitted, the array elements are separated with a comma (",").
		If separator is an empty string, all elements are joined without any characters in between them.

▼separator examples

var a = ['Wind', 'Water', 'Fire'];
a.join();      // 'Wind,Water,Fire'
a.join(', ');  // 'Wind, Water, Fire'
a.join(' + '); // 'Wind + Water + Fire'
a.join('');    // 'WindWaterFire'

 

[Return Value]

A string with all array elements joined.
: If arr.length is 0(If an element is undefined, null or an empty array []), the empty string is returned.

This method will not change the original array

 

@

www.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join