Slice & Substring (JavaScript)

Okay, this time I put this article in English, because it's more straightforward than translating to Indonesian language.

slice() works like substring() with a few different behaviors.

Syntax: string.slice(start, stop);
Syntax: string.substring(start, stop);

Notes on substring():

• If start equals stop, it returns an empty string.
• If stop is omitted, it extracts characters to the end of the string.
• If either argument is less than 0 or is NaN, it is treated as if it were 0.
• If either argument is greater than the string's length, either argument will use the string's length.
• If start > stop, then substring will swap those 2 arguments.

Notes on slice():

• If stop is omitted, slice extracts chars to the end of the string, exactly like substring().
• If start > stop, slice() will NOT swap the 2 arguments.
• If start is negative, slice() will set char from the end of string, exactly like substr() in Firefox. This behavior is observed in both Firefox and IE.
• If stop is negative, slice() will set stop to: (string.length – 1) – stop (original value).

For  .substr() and .slice(), they are notably different!

.slice() is:

string.slice(beginIndex, endIndex)

Whereas .substr() is:

string.substr(beginIndex, length);

So for example, if we have "1234" and wanted "23", it would be:

"1234".slice(1,3)
//or...
"1234".substr(1,2)

They also have different behavior for the more-rarely used negative indexes, look at the MDC documentation for .slice() and .substr() for full descriptions.

Source: StackOverflow