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.

string

String containing characters produced by the character generator defined for unit. By default, unit defaults to 'grapheme-ascii'. Our units have been built from documents linked to the specifications of Unicode 15.

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.

string​

string