File

Generate file content values.

base64String

Base64 string containing characters produced by fc.base64().

Provide valid base64 strings: length always multiple of 4 padded with '=' characters.

Signatures:

fc.base64String()
fc.base64String({minLength?, maxLength?, size?})

with:

minLength? — default: 0 — minimal number of characters (included)
maxLength? — default: 0x7fffffff more — maximal number of characters (included if multiple of 4)
size? — default: undefined more — how large should the generated values be?

When using minLength and maxLength make sure that they are compatible together. For instance: asking for minLength=2 and maxLength=3 is impossible for base64 strings as produced by the framework

Usages:

fc.base64String();
// Examples of generated values: "", "J7B8AB/V89==", "3H9Pr5M=", "bv6z", "V/GSu73r"…

fc.base64String({ maxLength: 8 });
// Note: Any base64 string containing up to 8 (included) characters
// Examples of generated values: "f3A+nr==", "37/7", "", "wC9q", "BLop9YK="…

fc.base64String({ minLength: 8 });
// Note: Any base64 string containing at least 8 (included) characters
// Examples of generated values: "f3A+nrd9UefIFrD27/==", "7/7+S88//DE/6M9QPAFg", "9refalueODsnam==", "toString", "callerkeyC8="…

fc.base64String({ minLength: 4, maxLength: 12 });
// Note: Any base64 string containing between 4 (included) and 12 (included) characters
// Examples of generated values: "YQ7D/IU8fE+2", "tjhMHtq9", "property", "9lm8Vx7bBF==", "roto"…

Resources: API reference.
Available since 0.0.1.

json

JSON compatible string representations of instances. Can produce string representations of basic primitives but also of deep objects.

The generated values can be parsed by JSON.parse. All the string values (from keys to values) are generated using fc.string().

Signatures:

fc.json()
fc.json({depthSize?, maxDepth?, noUnicodeString?, stringUnit?})

with:

depthSize? — default: undefined more — how much we allow our recursive structures to be deep?
maxDepth? — default: Number.POSITIVE_INFINITY — maximal depth of generated objects
noUnicodeString? — default: true — toggle on/off the generation of strings used either as keys or values of the instance and including non-ascii characters — shadowed by stringUnit
stringUnit? — default: undefined — customize the set of characters being used by the string arbitrary

Usages:

fc.json();
// Examples of generated values:
// • "[\"oU6LT>'\",{\"QZ#YUZNw\":null,\"#\":null,\")>*\":{\"q&B1cUDn=\":\"CZTPpisxH\",\"u`)})\":\"_a-\",\"\":null},\"dY~Dn>k\":true,\"=nC#&uS5l%\":\"0\\\"j-o,JV\",\"TX[OKj\":-1.7084671585468263e+151,\"\\\"\":true,\"@(:<LUW\":\"s-JYYB\"},[]]"
// • "\"al[->g\""
// • "null"
// • "-1e-322"
// • "[null,-1.5485504457576672e+192,null,{},-1.417727947024272e-287,null,null,null]"
// • …

fc.json({ noUnicodeString: false });
// Examples of generated values:
// • "{}"
// • "[{\"󜁳򁿳򎗯􈤘񖇅\":null,\"򈷩𫨹􏥃򤵪񥉨񢦜꣙\":[null,\"򉲨򛨰𜥲񆠉򁀿񇆾􀤯񾱄\"],\"__def\":\"񥛡\",\"𴂏򰷳𩪎񡨫\":true,\"2􏿺\":\"\",\"􍥚󛂾𓴒\":false},[3.5931489320423776e+139,[true,\"󌘅񪜆󗛃󎩻𙹖򞠚򺳵񨶖\",false,{\"􊆪򓔝򘥬𔧥󴓌򩁆\":null,\"\":\"󌽡𗀥󚨿󊭹򎻎񀓜򧅘򏜣󨓚񯄈\",\"𽸧򽂵񯆎񷡰𑴵񞱒\":[true,\"򀲑򿒦\",true,\"􊔹񒚡𣉟𳡸񮋳󳝶\",false,-4.119935921393037e+259,null,-8.9364525362984475e+248]},\"򸀿󳿴񥘡򪠾򃰧򣖏\",\"󱝇򹢖𬂏񠤫󴕠򒐧\"]],[false,-6.0502670401327095e+112,1.1096547717393745e-177,null,null,null,false,[null,\"󘳑㨦𭦄񱹂𚃜򅅪󪃗򟓓󊕝򠗺\",1.288654068889961e-213,null,1.6406299790913147e-206]]]"
// • "\"򁤇𫍯􏿬$񞋰%򟱉򳟔󽐾\""
// • "[null,[{\"壏\":true,\"𮀳񠍞󗈌\":\"耕򰶤䰅𸬣\",\"\":null,\"𘥣񯙝𖹟󗨟𯵽򿈤􊇦󣌙󸫨󸅔\":true,\"󒾠򈄕󬀘𚨶󍋤񃞜𮢌􇶸񏭘\":null,\"񮹷񀚤󷅓󰪼􀆌𥰂𫃩𧆔𹷹󭼜\":true,\"󛶋򣄚񼇏򡭇󹃤󢁬𞲢\":-4.059178361848322e-91,\"򉁀򠾫𓦞𑬞󵫽򏥷񹺏􌗈\":true},null],[3.6448982683876056e+131]]"
// • "[null,false]"
// • …

fc.json({ maxDepth: 0 });
// Examples of generated values: "null", "\"T\"", "-1.6050118268310372e-215", "true", "\"Ep\""…

fc.json({ maxDepth: 1 });
// Examples of generated values: "{\"V~<\\\"#}\":\"apply\"}", "{\"DZ&2@~yE\":4.016561322014934e-232}", "null", "true", "{}"…

fc.json({ depthSize: 'medium' });
// Examples of generated values:
// • "2.6e-322"
// • "[\"v!56\",true,{\"n.Z-KP\":\"WeB\",\"%sT\":true,\"+vJj71IB1\":\"p\\\"9|V\\\".\",\"B~U)!j6>:0\":\"?]2R)hy\",\"<C\":5.763682596504741e-124,\"g\":5.506486779037679e+86,\"^\":false,\"0beh\":null},null,true,false,null]"
// • "-1e-322"
// • "{\"valueOf\":{\"hCu2[\":{\"}t\":{\"rC,RK\":false,\"|sD.+@+\":\"K?e5tLzu\"},\"*4 80r\":{\"=c8x 3^\":\"\",\"bv2;Pdc\":266593828340.0835,\"&F{b*Ow:tH\":3.854574422896131e-236,\"\":-3.136445144286352e-152,\"7 a[$t.f[\":null,\"S\":true,\"VdF\":\"zr}U[\"},\"suNX+*`0y\":null,\"GO*sBjC8G1\":{\"Bx5_>&C'l\":\"<\",\"8qI\":1.5292990047864634e-116,\"hKPYD5\":-1.7059350714655333e+80,\";-{\":false,\"-0/PeWhX)3\":\"-}|\",\"\":null,\"!\":\"H0(|XlzFMY\",\"peo`:V\":\"%#BLcJMT\",\"T+FOe$\":true,\"Z7\":null},\"zCA'ft\\\\l^J\":[null]}},\";oU_&9\":{\"b\":{\"\":null,\"%C\":\"+Lf\",\"%6>\":1.797693134862311e+308,\"}vi!#D[G\\\\\":null,\"g.q&2evf\":\"C^tirM8d?,\",\"4t4aCG\":true,\"$n\\\"\":\"(IbE\"},\"|Bt[MInNOk\":null,\"#&$gzzy\":null,\"bd7cNTL\":[null,\"D\",null,1.627654078166552e+223,null,null,\"g\",\"gr\",-1.137436331927833e+42,-3.0030877534684717e+142],\" j]\":{\"hlI1\":null,\"e1$j@B\":null,\"-!\":\"7<!94\",\"fM@\":-4.396133099620614e-146,\"RwN]?%U@b7\":null,\"KB\":true,\"k=z<\":1.8766725492972305e-96,\"\":null,\"~b1>42%\":null,\"G\":null},\":v FiA\":\"k\",\"VlI okG\":-1.4e-322,\"f\":null,\"%w*B}\":true,\"\":\"apply\"},\"l\":[7.6086682491958856e-146,{\"5\":\"\",\"Y)s.a\":null,\"0y]0ca@qm2\":\"inPS~K2q{\",\"S*Z*f&=\":null,\"-=u\":false,\"v.P\":-7.067638177674602e+76},\"$~1<?Pv_\",null,[2.219624217009348e-22,-9.770861754123764e+110,true,null,\"/.1Q%v\",null,null],true,1.2718114310572915e+272,true,true]}"
// • "{\"L|hZ\":{\"~(\":\"4jKldvae;X\",\"NU(b\":null,\"\":4.163017031290256e+162,\"K\\\"F\":null,\"o<|c\":true,\"< bZ] \":false,\"wS,Riq}CV4\":-5.298684866824531e+64},\"3md/a<_r{\\\"\":{},\"-Rcc`3_\":[true,\"xuY=Hd6 \",{\"5e(_%d9^0d\":null,\"^q#$iu\":null},1.973826918030355e-291,{\"k\":-2.1122181366513202e+135,\"fYxj@\":-1.351657689147719e-183,\"2<+2nm%\":6.329905233731848e-285,\"4y.!XKqc\":null,\"CSaX}b\":\"`J_fU\",\"nc\":null,\"OXR>\":\"^xW!\"}],\"\":{\"d1}%eQ=\":{\":\":false,\"bO9,.DM\":false}},\"4iK-j!9hx\":{\"xK^[~mT\":null,\"l2$7G5(\":{\"4%' 15&pK\":true,\"[$@Y`\":\"5EHH_d.@|\",\"\":\"\\\\\",\"E~[./|O3\":-9.129273010709225e+288},\"K\\\\;/4elg|$\":null,\"jr\":-1.0758585287978389e-274,\"~@S\":\"\",\",*I)0\":\"]7\",\"-!:NF\":true,\"(Dp\":\")3Fd\",\"(:^0XUcye2\":null}}"
// • …

Resources: API reference.
Available since 0.0.7.

jsonValue

Generate any value eligible to be stringified in JSON and parsed back to itself - in other words, JSON compatible instances.

As JSON.parse preserves -0, jsonValue can also have -0 as a value. jsonValue must be seen as: any value that could have been built by doing a JSON.parse on a given string.

Note

JSON.parse(JSON.stringify(value)) is not the identity as -0 is changed into 0 by JSON.stringify.

Signatures:

fc.jsonValue()
fc.jsonValue({depthSize?, maxDepth?, noUnicodeString?, stringUnit?})

with:

depthSize? — default: undefined more — how much we allow our recursive structures to be deep?
maxDepth? — default: Number.POSITIVE_INFINITY — maximal depth for generated objects (Map and Set included into objects)
noUnicodeString? — default: true — toggle on/off the generation of strings used either as keys or values of the instance and including non-ascii characters — shadowed by stringUnit
stringUnit? — default: undefined — customize the set of characters being used by the string arbitrary

Usages:

fc.jsonValue();
// Examples of generated values:
// • true
// • {"a":false,"&{v%":true,"O}u&;O":"ef","^69fY8G[M":false,"^%":null,"iC":-2.11992523062418e-82,"F%]8l0g6|":null}
// • [{"^":true,"1Y??Vih":-379313284684773500000,"_5zzvjCE":"B","B561n_":"2","eqHZM9R":null},1.2791945048214157e-72]
// • false
// • [null,true,true,"`l+$I","kSros",null]
// • …

fc.jsonValue({ noUnicodeString: false });
// Examples of generated values:
// • ["򴾼󹤷𡅤񤱓򛗡"]
// • {"􎵔򲁼򀎈𸝔􃌅􊿛񹙦":[false],"򨊗𤮈𡈡󵑑񗀏򏗔𙔔𐸵񇘼":556603.8398649627,"􏿽+򸑽":{"񐀞󴕃󙉅񂊠𴛐󻕀㢋񦔘":true,"񊈒􋚭󷪙𫪀󌧶񉝒𱣆":null,"":5.539268054957889e+74,"򦹷":"񜝍⌳򻍜񇓷񖋦","񥸱񥊔򦹗":4.847354156832373e-25,"񜂑򹏁󞦐":"𻬫𳤲󵹃򕏧񁃵","𓧎𖰦":false,"󛻳򏜚񃛷񌛑𝜀󞅤񪉺":false}}
// • [null,["󿦼񌅡󯻾𝀹򲓋񁆺񐿏󃢰",-2.4628931920258706e-282,null,false,2.681696006505804e-238,"򢰮"]]
// • "򐐩"
// • []
// • …

fc.jsonValue({ maxDepth: 0 });
// Examples of generated values: true, null, false, "prototype", "L4)5M"…

fc.jsonValue({ maxDepth: 1 });
// Examples of generated values:
// • 1.1084525170506737e-156
// • [null,"co",null]
// • [null,null]
// • [null,"_",-4.808983581881553e-305,1.3122779113832298e-87,"<tiQ8",null]
// • true
// • …

fc.statistics(fc.jsonValue(), (v) => {
  function size(n) {
    if (Array.isArray(n)) return 1 + n.reduce((acc, child) => acc + size(child), 0);
    if (typeof n === 'object' && n) return 1 + Object.values(n).reduce((acc, child) => acc + size(child), 0);
    return 1;
  }
  const s = size(v);
  let lower = 1;
  const next = (n) => (String(n)[0] === '1' ? n * 5 : n * 2);
  while (next(lower) <= s) {
    lower = next(lower);
  }
  return `${lower} to ${next(lower) - 1} items`;
});
// Computed statistics for 10k generated values:
// For size = "xsmall":
// • 1 to 4 items..100.00%
// For size = "small":
// • 1 to 4 items....43.79%
// • 10 to 49 items..38.40%
// • 5 to 9 items....17.64%
// • 50 to 99 items...0.17%
// For size = "medium":
// • 50 to 99 items......35.06%
// • 1 to 4 items........33.88%
// • 10 to 49 items......20.48%
// • 100 to 499 items....10.21%
// • 500 to 999 items.....0.33%

fc.statistics(fc.jsonValue({ maxDepth: 2 }), (v) => {
  function size(n) {
    if (Array.isArray(n)) return 1 + n.reduce((acc, child) => acc + size(child), 0);
    if (typeof n === 'object' && n) return 1 + Object.values(n).reduce((acc, child) => acc + size(child), 0);
    return 1;
  }
  const s = size(v);
  let lower = 1;
  const next = (n) => (String(n)[0] === '1' ? n * 5 : n * 2);
  while (next(lower) <= s) {
    lower = next(lower);
  }
  return `${lower} to ${next(lower) - 1} items`;
});
// Computed statistics for 10k generated values:
// For size = "xsmall":
// • 1 to 4 items..100.00%
// For size = "small":
// • 1 to 4 items....44.64%
// • 5 to 9 items....34.00%
// • 10 to 49 items..21.36%
// For size = "medium":
// • 1 to 4 items......34.60%
// • 50 to 99 items....33.01%
// • 10 to 49 items....26.56%
// • 100 to 499 items...4.49%
// • 5 to 9 items.......1.34%

Resources: API reference.
Available since 2.20.0.

lorem

Lorem ipsum values.

Signatures:

fc.lorem()
fc.lorem({maxCount?, mode?, size?})

with:

maxCount? — default: 0x7fffffff more — if mode is "words": lorem ipsum sentence containing at most maxCount sentences, otherwise: containing at most maxCount words_
mode? — default: "words" — enable sentence mode by setting its value to "sentences"
size? — default: undefined more — how large should the generated values be?

Usages:

fc.lorem();
// Examples of generated values:
// • "magna ullamcorper iaculis purus nec"
// • "lorem"
// • "eu semper lectus mauris sed in nulla non scelerisque massa enim cras"
// • "mauris arcu cras molestie"
// • "euismod"
// • …

fc.lorem({ maxCount: 3 });
// Examples of generated values: "duis enim nonummy", "consequat pharetra iaculis", "sollicitudin mi curabitur", "faucibus", "cursus sit ac"…

fc.lorem({ maxCount: 3, mode: 'sentences' });
// Examples of generated values:
// • "Nec, dolor congue vitae pellentesque orci amet."
// • "Amet augue metus nibh rhoncus nulla morbi dui sed ac. Aliquam massa, et vestibulum integer suscipit magna pellentesque nonummy. Mi tellus, posuere vestibulum nibh."
// • "Ullamcorper orci ipsum diam ultrices convallis mollis, ullamcorper. Vitae faucibus bibendum ligula."
// • "Elementum semper iaculis ligula mauris ipsum mauris. Cursus massa nulla semper feugiat, sed scelerisque."
// • "Vitae. Dolor primis aenean convallis adipiscing mauris in odio ante. Massa, faucibus."
// • …

Resources: API reference.
Available since 0.0.1.

base64String​

json​

jsonValue​

lorem​

base64String

json

jsonValue

lorem