indexStart

The index of the first character to include in the returned substring.

indexEndOptional

The index of the first character to exclude from the returned substring.

A new string containing the extracted section of the string.

slice() extracts the text from one string and returns a new string.

slice() extracts up to but not includingindexEnd. For example,str.slice(4, 8) extracts the fifth character through the eighth character (characters indexed4,5,6, and7):

              indexStart        indexEnd                  ↓               ↓| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 || T | h | e |   | m | i | r | r | o | r |                  m   i   r   r                 _______________                      ↑                    Result

• IfindexStart >= str.length, an empty string is returned.
• IfindexStart < 0, the index is counted from the end of the string. More formally, in this case, the substring starts atmax(indexStart + str.length, 0).
• IfindexStart is omitted,undefined, or cannot beconverted to a number, it's treated as0.
• IfindexEnd is omitted orundefined, or ifindexEnd >= str.length,slice() extracts to the end of the string.
• IfindexEnd < 0, the index is counted from the end of the string. More formally, in this case, the substring ends atmax(indexEnd + str.length, 0).
• IfindexEnd <= indexStart after normalizing negative values (i.e.,indexEnd represents a character that's beforeindexStart), an empty string is returned.

The following example usesslice() to create a new string.

const str1 = "The morning is upon us."; // The length of str1 is 23.const str2 = str1.slice(1, 8);const str3 = str1.slice(4, -2);const str4 = str1.slice(12);const str5 = str1.slice(30);console.log(str2); // he mornconsole.log(str3); // morning is upon uconsole.log(str4); // is upon us.console.log(str5); // ""

The following example usesslice() with negative indexes.

const str = "The morning is upon us.";str.slice(-3); // 'us.'str.slice(-3, -1); // 'us'str.slice(0, -1); // 'The morning is upon us'str.slice(4, -1); // 'morning is upon us'

This example counts backwards from the end of the string by11 to find thestart index and forwards from the start of the string by16 to find the endindex.

console.log(str.slice(-11, 16)); // "is u"

Here it counts forwards from the start by11 to find the start index andbackwards from the end by7 to find the end index.

console.log(str.slice(11, -7)); // " is u"

These arguments count backwards from the end by5 to find the start indexand backwards from the end by1 to find the end index.

console.log(str.slice(-5, -1)); // "n us"

• String.prototype.substr()
• String.prototype.substring()
• Array.prototype.slice()