String.prototype.slice()

The slice() method extracts a section of a string and returns it as a new string, without modifying the original string.

Syntax

slice(indexStart)
slice(indexStart, indexEnd)

Parameters

• indexStart
  • : The index of the first character to include in the returned substring.
• indexEnd optional
  • : The index of the first character to exclude from the returned substring.

Return value

A new string containing the extracted section of the string.

Description

slice() extracts the text from one string and returns a new string. Changes to the text in one string do not affect the other string.

slice() extracts up to but not including indexEnd. For example, str.slice(1, 4) extracts the second character through the fourth character (characters indexed 1, 2, and 3).

• If indexStart >= str.length, an empty string is returned.
• If indexStart < 0, the index is counted from the end of the string. More formally, in this case, the substring starts at max(indexStart + str.length, 0).
• If indexStart is omitted, undefined, or cannot be converted to a number (using Number()), it's treated as 0.
• If indexEnd is omitted, undefined, or cannot be converted to a number (using Number()), or if indexEnd >= str.length, slice() extracts to the end of the string.
• If indexEnd < 0, the index is counted from the end of the string. More formally, in this case, the substring ends at max(indexEnd + str.length, 0).
• If indexEnd <= indexStart after normalizing negative values (i.e. indexEnd represents a character that's before indexStart), an empty string is returned.