strings_xxx 1.0.0

Provides a set of String related functions

A package of handy string functions.

definitions

• A blank string is a string which contains only whitespace or is null
• An empty string is a string of zero length or is null

nullToEmpty

String nullToEmpty(String? value)

If [value] is null we return an zero length string otherwise we return [value].

    expect(Strings.nullToEmpty(null), equals(''));
    expect(Strings.nullToEmpty('abc'), equals('abc'));

isEmpty

Returns true if the [value] is null, or is a zero length String

bool isEmpty(String? value)

   expect(Strings.isEmpty(null), isTrue);
   expect(Strings.isEmpty('  '), isFalse);
   expect(Strings.isEmpty('abc'), isFalse);

isNotEmpty

Returns true if the [value] is not null and is a zero length String

bool isNotEmpty(String? value)

    expect(Strings.isNotEmpty(null), isFalse);
    expect(Strings.isNotEmpty('  '), isTrue);
    expect(Strings.isNotEmpty('abc'), isTrue);

isBlank

Returns true if the [value] is null or Blank. Whitespace is ignored

bool isBlank(String? value)

    expect(Strings.isBlank(null), isTrue);
    expect(Strings.isBlank('  '), isTrue);
    expect(Strings.isBlank('abc'), isFalse);

isNotBlank

Returns true if the [value] is not null and not Blank. A string containing only whitespace is considered blank. See: [isNotEmpty] to check for non-zero length string.

bool isNotBlank(String? value)

    expect(Strings.isNotBlank(null), isFalse);
    expect(Strings.isNotBlank('  '), isFalse);
    expect(Strings.isNotBlank('abc'), isTrue);

orElse

If [value] is null the [elseValue] is returned otherwise [value] is returned.

String orElse(String? value, String elseValue)

   expect(Strings.orElse(null, 'one'), equals('one'));
   expect(Strings.orElse('', 'one'), equals(''));

right

Returns all characters from [value] starting at [fromRight] inclusive.

If [fromRight] is outside the bounds of [value] then an [RangeError] is thrown.

String right(String value, int fromRight)

    expect(Strings.right('one', 0), equals('one'));
    expect(Strings.right('one', 1), equals('ne'));
    expect(Strings.right('one', 2), equals('e'));
    expect(Strings.right('one', 3), equals(''));
    expect(() => Strings.right('one', 4), throwsA(isA<RangeError>()));

left

Returns the first [fromLeft] characters from [value] If [fromLeft] is longer than [value] then an [RangeError] is thrown.

String left(String value, int fromLeft)

    expect(Strings.left('one', 0), equals(''));
    expect(Strings.left('one', 1), equals('o'));
    expect(Strings.left('one', 2), equals('on'));
    expect(Strings.left('one', 3), equals('one'));
    expect(() => Strings.left('one', 4), throwsA(isA<RangeError>()));

isNumeric

Checks if [string] is a number by attempting to parse it as a double. INFINITY and NaN are not treated as numbers.

bool isNumeric(String? string)

 expect(Strings.isNumeric(null), isFalse);
    expect(Strings.isNumeric(''), isFalse);
    expect(Strings.isNumeric('x'), isFalse);
    expect(Strings.isNumeric('123x'), isFalse);
    expect(Strings.isNumeric('123'), isTrue);
    expect(Strings.isNumeric('+123'), isTrue);
    expect(Strings.isNumeric('123.456'), isTrue);
    expect(Strings.isNumeric('-123'), isTrue);
    expect(Strings.isNumeric(double.infinity.toString()), isFalse);
    expect(Strings.isNumeric(double.nan.toString()), isFalse);
    expect(Strings.isNumeric('0x123'), isFalse);

abbreviate

Abbreviate a string to [maxWidth] by truncating the string and adding '...' to then truncated string.

The minimum value for [maxWidth] is 4

String abbreviate(final String str, final int maxWidth, {int offset = 0})

    expect(Strings.abbreviate('one two', 4), equals('o...'));
    expect(Strings.abbreviate('one two', 5), equals('on...'));
    expect(Strings.abbreviate('one two', 6), equals('one...'));
    expect(Strings.abbreviate('one two', 7), equals('one two'));

properCase

Converts [sentence] to proper case by capitalising the first letter of each word and forcing all other characters to lower case.

String properCase(String sentence)

    expect(Strings.properCase(''), equals(''));
    expect(Strings.properCase('one'), equals('One'));
    expect(Strings.properCase('one two three'), equals('One Two Three'));
    expect(Strings.properCase('ONE'), equals('One'));
    expect(Strings.properCase('ONE TWO THREE'), equals('One Two Three'));

equals

Safely compares two strings. If both are null returns true If one of them is null returns false if both are the same returns true.

bool equals(String? lhs, String? rhs)

    expect(Strings.equals(null, null), isTrue);
    expect(Strings.equals('one', null), isFalse);
    expect(Strings.equals(null, 'one'), isFalse);
    expect(Strings.equals('one', 'one'), isTrue);
    expect(Strings.equals('one', 'two'), isFalse);