description

# trim method Null safety

String trim ()

Returns the string without any leading and trailing whitespace.

If the string contains leading or trailing whitespace, a new string with no leading and no trailing whitespace is returned:

    '\tDart is fun\n'.trim(); // 'Dart is fun'

Otherwise, the original string itself is returned:

    var str1 = 'Dart';
    var str2 = str1.trim();
    identical(str1, str2);    // true

Whitespace is defined by the Unicode White_Space property (as defined in version 6.2 or later) and the BOM character, 0xFEFF.

Here is the list of trimmed characters according to Unicode version 6.3:

        0009..000D    ; White_Space # Cc   <control-0009>..<control-000D>
        0020          ; White_Space # Zs   SPACE
        0085          ; White_Space # Cc   <control-0085>
        00A0          ; White_Space # Zs   NO-BREAK SPACE
        1680          ; White_Space # Zs   OGHAM SPACE MARK
        2000..200A    ; White_Space # Zs   EN QUAD..HAIR SPACE
        2028          ; White_Space # Zl   LINE SEPARATOR
        2029          ; White_Space # Zp   PARAGRAPH SEPARATOR
        202F          ; White_Space # Zs   NARROW NO-BREAK SPACE
        205F          ; White_Space # Zs   MEDIUM MATHEMATICAL SPACE
        3000          ; White_Space # Zs   IDEOGRAPHIC SPACE

        FEFF          ; BOM                ZERO WIDTH NO_BREAK SPACE

Some later versions of Unicode do not include U+0085 as a whitespace character. Whether it is trimmed depends on the Unicode version used by the system.

## Implementation

    String trim();