String

Generate string values.

tip

If you want to join several strings together: refer to our combiners section. We have some built-in combiners working exclusively on string values.

hexaString

Hexadecimal string containing characters produced by fc.hexa().

Signatures:

• fc.hexaString() — deprecated since v3.22.0 (more details at #5233)
• fc.hexaString({minLength?, maxLength?, size?}) — deprecated since v3.22.0 (more details at #5233)

with:

• minLength? — default: 0 — minimal number of characters (included)
• maxLength? — default: 0x7fffffff more — maximal number of characters (included)
• size? — default: undefined more — how large should the generated values be?

Usages:

fc.hexaString();
// Examples of generated values: "251971", "", "a9", "742e6c86e", "39350b163"…

fc.hexaString({ maxLength: 3 });
// Note: Any hexadecimal string containing up to 3 (included) characters
// Examples of generated values: "1", "", "2ef", "2a", "6e3"…

fc.hexaString({ minLength: 3 });
// Note: Any hexadecimal string containing at least 3 (included) characters
// Examples of generated values: "1021a292c2d306", "e4660fd014ae290", "2ef914a5d7ffe9df", "2a212", "05dd1"…

fc.hexaString({ minLength: 4, maxLength: 6 });
// Note: Any hexadecimal string containing between 4 (included) and 6 (included) characters
// Examples of generated values: "b4ccb", "e51d", "b3e093", "383f", "27bd"…

Resources: API reference.
Available since 0.0.1.

string

String containing characters produced by the character generator defined for unit. By default, unit defaults to fc.char().

Signatures:

• fc.string()
• fc.string({minLength?, maxLength?, size?, unit?})

with:

• unit? — default: 'grapheme-ascii' — how to generate the characters that will be joined together to create the resulting string
• minLength? — default: 0 — minimal number of units (included)
• maxLength? — default: 0x7fffffff more — maximal number of units (included)
• size? — default: undefined more — how large should the generated values be?

Usages:

fc.string();
// Examples of generated values: "JT>\"C9k", "h]iD\"27;", "S", "n\\Ye", ""…

fc.string({ maxLength: 3 });
// Note: Any string containing up to 3 (included) characters
// Examples of generated values: "", "ref", "?D", "key", "}"…

fc.string({ minLength: 3 });
// Note: Any string containing at least 3 (included) characters
// Examples of generated values: "Pv-^X_t", "bind", "?DM", "iEjK.b?^O", "}~}S"…

fc.string({ minLength: 4, maxLength: 6 });
// Note: Any string containing between 4 (included) and 6 (included) characters
// Examples of generated values: "Trxlyb", "&&@%4", "s@IO", "0\"zM", "}#\"$"…

fc.string({ unit: 'grapheme' });
// Note: Any string made only of printable graphemes possibly made of multiple code points.
// With 'grapheme', minLength (resp. maxLength) refers to length in terms of graphemes (visual entities).
// As an example, "\u{0061}\u{0300}" has a length of 1 in this context, as it corresponds to the visual entity: "à".
// Examples of generated values: "length", "🡓𑨭", "🚌ﾱॶ🥄ၜ㏹", "key", "callஈcall"…

fc.string({ unit: 'grapheme-composite' });
// Note: Any string made only of printable graphemes.
// With 'grapheme-composite', minLength (resp. maxLength) refers to length in terms of code points (equivalent to visual entities for this type).
// Examples of generated values: "🭃𖼰𱍊alleef", "#", "𝕃ᖺꏪ🪓ሪ㋯𑼓𘠴𑑖", "", "\"isP"…

fc.string({ unit: 'grapheme-ascii' });
// Note: Any string made only of printable ascii characters.
// With 'grapheme-composite', minLength (resp. maxLength) refers to length in terms of code units aka chars (equivalent to code points and visual entities for this type).
// Examples of generated values: "+", "y\\m4", ")H", "}q% b'", "ZvT`W"…

fc.string({ unit: 'binary' });
// Note: Results in strings made of any possible combinations of code points no matter how they join between each others (except half surrogate pairs).
// With 'binary', minLength (resp. maxLength) refers to length in terms of code points (not in terms of visual entities).
// As an example, "\u{0061}\u{0300}" has a length of 2 in this context, even if it corresponds to a single visual entity: "à".
// Examples of generated values: "length", "𒇖ᴣ󠓋򹕎󥰆󕃝󗅛񞙢򂓥񋂐", "", "󹶇񺓯𢊊񦺖", "key"…

fc.string({ unit: 'binary-ascii' });
// Note: Results in strings made of any possible combinations of ascii characters (in 0000-007F range).
// With 'binary-ascii', minLength (resp. maxLength) refers to length in terms of code units aka chars (equivalent to code points for this type).
// Examples of generated values: "c\\3\f\u0000\u001f\u00047", "M\u0006\fD!U\u000fXss", "", "s\u0000", "\n\u0006tkK"…

fc.string({ unit: fc.constantFrom('Hello', 'World') });
// Note: With a custom arbitrary passed as unit, minLength (resp. maxLength) refers to length in terms of unit values.
// As an example, "HelloWorldHello" has a length of 3 in this context.
// Examples of generated values: "", "Hello", "HelloWorld", "HelloWorldHello", "WorldWorldHelloWorldHelloWorld"…

Resources: API reference.
Available since 0.0.1.

asciiString

ASCII string containing characters produced by fc.ascii().

Signatures:

• fc.asciiString() — deprecated since v3.22.0, prefer string (more details at #5233)
• fc.asciiString({minLength?, maxLength?, size?}) — deprecated since v3.22.0, prefer string (more details at #5233)

with:

• minLength? — default: 0 — minimal number of characters (included)
• maxLength? — default: 0x7fffffff more — maximal number of characters (included)
• size? — default: undefined more — how large should the generated values be?

Usages:

fc.asciiString();
// Examples of generated values: "\f@D", "hp", "q#dO~?@", "Qad", "5eHqc"…

fc.asciiString({ maxLength: 3 });
// Note: Any ascii string containing up to 3 (included) characters
// Examples of generated values: "6", "", "ty", ",", "k"…

fc.asciiString({ minLength: 3 });
// Note: Any ascii string containing at least 3 (included) characters
// Examples of generated values: "603e", "6W\u001b^tR-\n\n|", "efproto_\u001abhasOw", "$\u001c&\u0000R", "apply"…

fc.asciiString({ minLength: 4, maxLength: 6 });
// Note: Any ascii string containing between 4 (included) and 6 (included) characters
// Examples of generated values: "<&\u001e\u001b ", "bind", "dnGn\\2", "& % !", "__defi"…

Resources: API reference.
Available since 0.0.1.

unicodeString

Unicode string containing characters produced by fc.unicode().

Signatures:

• fc.unicodeString() — deprecated since v3.22.0, prefer string (more details at #5233)
• fc.unicodeString({minLength?, maxLength?, size?}) — deprecated since v3.22.0, prefer string (more details at #5233)

with:

• minLength? — default: 0 — minimal number of characters (included)
• maxLength? — default: 0x7fffffff more — maximal number of characters (included)
• size? — default: undefined more — how large should the generated values be?

Usages:

fc.unicodeString();
// Examples of generated values: ",", "뇇ⷍ돠", "", "穿ﺥ羊汉ힸ౨", "穙셣킲햗䊢鏶눏"…

fc.unicodeString({ maxLength: 3 });
// Note: Any unicode (from BMP-plan) string containing up to 3 (included) characters
// Examples of generated values: "", "꙰", "툌", "㮟୆", "a"…

fc.unicodeString({ minLength: 3 });
// Note: Any unicode (from BMP-plan) string containing at least 3 (included) characters
// Examples of generated values: "떚碱縢鰷釬ڤ撙", "竑૱toS", "꙰ꁺ蜱⫄ั", "__d", "툌뀪凛瞸㾡끴"…

fc.unicodeString({ minLength: 4, maxLength: 6 });
// Note: Any unicode (from BMP-plan) string containing between 4 (included) and 6 (included) characters
// Examples of generated values: "뿐噻⪃嫿垈", "ڣۡ觌뱇", "apply", "톥薦￾", "namea"…

Resources: API reference.
Available since 0.0.11.

string16bits

String containing characters produced by fc.char16bits().

Be aware that the generated string might appear invalid regarding the unicode standard as it might contain incomplete pairs of surrogate.

Signatures:

• fc.string16bits() — deprecated since v3.22.0 (more details at #5233)
• fc.string16bits({minLength?, maxLength?, size?}) — deprecated since v3.22.0 (more details at #5233)

with:

• minLength? — default: 0 — minimal number of characters (included)
• maxLength? — default: 0x7fffffff more — maximal number of characters (included)
• size? — default: undefined more — how large should the generated values be?

Usages:

fc.string16bits();
// Examples of generated values: "", "沉蹻!쯼&)噕￶", "獏", "嚷爇꡽邏䨫Ꝺ䟌", "ۆ딛楯씺"…

fc.string16bits({ maxLength: 3 });
// Note: Any string (not really legal ones sometimes) containing up to 3 (included) characters
// Examples of generated values: "", "ꃷ", "톽va", "뿤䵎悧", ""…

fc.string16bits({ minLength: 3 });
// Note: Any string (not really legal ones sometimes) containing at least 3 (included) characters
// Examples of generated values: "㝟佷㟧࿝譽먔", "ꃷ￱￷ꢒ￸", "톽valueOf", "key", "app"…

fc.string16bits({ minLength: 4, maxLength: 6 });
// Note: Any string (not really legal ones sometimes) containing between 4 (included) and 6 (included) characters
// Examples of generated values: "apply", "鹽\udc68鯻שּׂ", "땺\uda2f熑鉈뗻", "__def", "㓐줫曧ᒢ"…

Resources: API reference.
Available since 0.0.11.

fullUnicodeString

Unicode string containing characters produced by fc.fullUnicode().

Signatures:

• fc.fullUnicodeString() — deprecated since v3.22.0, prefer string (more details at #5233)
• fc.fullUnicodeString({minLength?, maxLength?, size?}) — deprecated since v3.22.0, prefer string (more details at #5233)

with:

• minLength? — default: 0 — minimal number of characters (included)
• maxLength? — default: 0x7fffffff more — maximal number of characters (included)
• size? — default: undefined more — how large should the generated values be?

Be aware that the length is considered in terms of the number of glyphs in the string and not the number of UTF-16 characters. As a consequence generatedString.length might be greater than the asked maximal length but [...generatedString].length will not and always be in the required range

Usages:

fc.fullUnicodeString();
// Examples of generated values: "򎅯񳓃󲢱򟭂", "󁵺涫򣤲󋣈󪷆", "󋅶񏵞󒽡󫺊񏽵", "􍄵򒂾󃉓", "񡚈"…

fc.fullUnicodeString({ maxLength: 3 });
// Note: Any unicode string containing up to 3 (included) code-points
// Examples of generated values: "򅉞񸟤󐋚", "􏿴", "􇢺", "", "󏫭"…

fc.fullUnicodeString({ minLength: 3 });
// Note: Any unicode string containing at least 3 (included) code-points
// Examples of generated values: "򅉞񸟤󐋚򲮃󺮞􍶈󂾓񅙎򼝄󒂁񌸩򌻜󎼿񺡓", "bind", "􇢺󣓺in", "%4􏿻propertyIs", "𒝰􇋧􏿫􏿱񧌫"…

fc.fullUnicodeString({ minLength: 4, maxLength: 6 });
// Note: Any unicode string containing between 4 (included) and 6 (included) code-points
// Examples of generated values: "call", "񛰖񞑑󱈋𨤎", "񉓁򔶍򣵵乀򠍾󢏘", ",valu", "󐣙󼃞񫎢󖫩𫅰𪂀"…

Resources: API reference.
Available since 0.0.11.