Skip to main content

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?})

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

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({ 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?})

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)

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({ 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.

unicodeJson​

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.unicodeString().

Signatures:

  • fc.unicodeJson()
  • fc.unicodeJson({depthSize?, maxDepth?})

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

Usages:

fc.unicodeJson();
// Examples of generated values:
// • "{\"ᥔßR\":{\"毟蜂唾缨Ⳡ眬\":{\"ᨢꉠ膃쩹㳩본⚁ꆾ䡫\":[\"毻쏳䉘빎酃糆ᚣ꥘ﻀ設\",1.4078094841036001e-67,\"┞\"],\"䧃䔝鉜饎ᠳ磙㾜\":\"㞫抮ꨛ퟼\",\"\":\"隻錒䕹嘗揣䱰̓ꖸ쳊\"},\"゙᯿錣龀槅꼌磱\":\"໮漠뻫ꅜ諩碶뒁铎\",\"㻁㞯鄄ᘕƛᙆ符緇矒鞹\":null,\"섿㺵ធ䕀\":true,\"㰘⮒泑ꚛ咸\":false,\"쵩傞漆뵠텐婢\":\"姍儵ඣ⽫⺞縺뗮㚃\",\"嫏ꨮ䣫\":-6.638526972924301e+52,\"ꔏ⽙䥽ѫ뢿䜻\":1.7943982562867058e+199}}"
// • "[]"
// • "[true,null,null,true,\"￿\",\"騨뷙ឣ푻꾴吉䚯\",false,null]"
// • "{\"᫄\":{\"坾ᦨ\":-1.9788421366816808e-82,\"駮㔽艕슑\":\"쓨♹訫뵥筭⪅䮹\",\"乓⃷觖\":null,\"㲾ペ钓睊虐\":80283984173685.53,\"泓ꑙᘤ⊫\":true,\"뤂䮽І眊ੋ竰\":\"\",\"鰲偅맟ద싏㠒嶬\":null},\"塜粼拺຿\":[null,true,null,{\"㧴䏄༳톏\":\"ꪰ篅酣ퟥ\",\"罟噝梹\":9.214173245947507e-111,\"녇몭㰡懬\":\"⻫캲뾦鱜퉵\",\"뀪妬鮯씅莝䮍䰃絡癿\":7.808042412941465e-176,\"䨺⺤ￗ莰⼵\":null,\"킀ᆍ闓⚘∥䓯옼\":null,\"\":null,\"ᮨ䌙杖ো䛞ᯈ\":false,\"鮁璟啵魬\":false,\"롘柺퇌⌓ꢏ⊓⟊渞望\":null}],\"혣㐀ࡰ䝯澨ဆ\":[[[\"⾒ꁿ\",\"㒱䖹Ѷ衔돵㤲畈\"],\"袼岌᧝퐿㾂\",null],\"䎿캮ᎍ쯍덪඘逹⃖釖\",true,null]}"
// • "true"
// • …

fc.unicodeJson({ maxDepth: 0 });
// Examples of generated values: "\"僘阘縝傚裷䀘\"", "null", "\"绠圞ⱺ\"", "true", "-2.3e-322"…

fc.unicodeJson({ maxDepth: 1 });
// Examples of generated values:
// • "[false,2.7321203973068163e+275,false,false,null,-9.218990816230408e-66]"
// • "{}"
// • "[\"ᅙ秱뵴ꇺ꿵玽鄧돟\",\"䕝\",null,\"䆩−ඍ㹏쭝း堥䗾兒\",\"샔ế\",false,true,\"缣켐駘\",\"Ӧ࠼䍝⇵鮤뉀㸓\"]"
// • "[false,\"❚姒쭧䠢\",1.4486395822832596e+27]"
// • "-1.8e-322"
// • …

fc.unicodeJson({ depthSize: 'medium' });
// Examples of generated values:
// • "\"荽醮郺旽粈㈾\""
// • "[null,{\"諄\":8.590711529263102e-8,\"薠롺□嬞⥨萳\":null,\"Ϊ᪤퟿䧂콂讵⨷噟쒖\":\"》㶄㞃ﾼॏ鼟所蛂\",\"ஒ䍛\":5.019276820129658e+122,\"佰㠋\":\"じ\",\"풧㌱옣\":null,\"돝쯧浹Ṋ኷\":true,\"紅ꪋ\":null,\"น騢∣⚓䅤앃\":2.7762012163115278e-173},true,true,\"ヲ볉ꇑ센鬥\",false,null,[true,null]]"
// • "false"
// • "{\"﷏꼲吽꡺㊐뿗茻\":null}"
// • "{\"腌ꊖ璄諰晜ᩝ鬬ᅗ\":true,\"\":{\"꽂ꥑ讧霵ꎽ歪䠯\":{\"눴Ó\":false}},\"嗒줹朗큶꡷獺\":[null,-4.581442170446369e-31,false,[-3.259931843441816e+90,[\"〚Ꮳ㟺㙰㒈♖暶ጼ\",null,true,\"䷷ﾵ쪲㝵谔挴\",\"殒ꬖ캩℻墊풺ⳁ䎕쳳\"],\"뺔櫆౅\",-5.824037460896646e-126,-1.2440275335144407e-110,2.2853367367043913e+207,false]],\"뺶閩頫䫉奈錏ꞛ\":\"ꦈ돬喵ᡝ떶ꨵ\",\"㾽ⲳ\":{\"극ꄆ橝촍毟\":\"呖턃䣯ꃪ淑湐愨鮫國\"}}"
// • …

Resources: API reference.
Available since 0.0.7.

unicodeJsonValue​

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, unicodeJsonValue can also have -0 as a value. unicodeJsonValue 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.unicodeJsonValue()
  • fc.unicodeJsonValue({depthSize?, maxDepth?})

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)

Usages:

fc.unicodeJsonValue();
// Examples of generated values:
// • null
// • [-4.295089174387055e-293,false,{"㾆⇈᎒ཱུ紻ﾷ":true,"膩᜸Ⱒᰑ䴿ㅓ붻":true,"㤫勮":null,"常洭":"❀紩푮뗼","":false,"遐伒㖤⩿":null,"쾪ꉱ絿ޒ":-1.6050931064928954e-96},null]
// • 3.4453237274410463e+71
// • []
// • [null,[null,{"鞘":false,"ᚄ秈搉糛힘ﯨ⯞":{"嗙":false,"뚹퐒孵ᱚ鼊":true,"ၓ醦ꨱ鲖䕬⁅蓌碈":false,"⭏횓醉ῂａ艒":null,"ﵦᙏ亚":-1.0765809081688447e-68,"麈껾땀ẚ㖡轹邹":2.7214577245022765e-88,"♔擥է宑놰꼒죵셃芮㱝":true},"ᡟ⽔䞊ɮ뽪":true}],"姖魡",{"죞鹕":null,"":"߸⸷","靄誾Ờꛙ࿠䞵ퟣ":"芓䞧굞늢뺄蹁ᮿ훱","䚬":-6.95950666926601e+110,"⹊꓌䘙࿈倡淕":"䚾忭㋟킛긮倹鷀","☂㰿㛈瓥⸸팭ުꊵ":"鞚꿖磆Ꮄゑꖦ","梣끲":2.609294368689059e-298,"팽":true}]
// • …

fc.unicodeJsonValue({ maxDepth: 0 });
// Examples of generated values: "Ĕ讆層ꦍ쩖䊼᛽ꙋ", null, 1.7976931348623047e+308, "", 2e-323…

fc.unicodeJsonValue({ maxDepth: 1 });
// Examples of generated values:
// • {"讆層ꦍ쩖䊼":true,"婝㖿ﺚ㔶벑Ἴ¤ﻣ诗":true,"蝌䥶膢瓣䥛䫀姐᥺":true,"ᓘ箜睺閊膛景븃犟":null,"ﯼ⛺㴞撟":true,"":false,"㍋豈漸核":-1.7683978910198014e+45,"玳":null,"境鲖":"뫞ຳ䐀啔"}
// • 1.7398076905782003e-265
// • "㩵詫,"
// • []
// • {"햧ཧ觌♘䣯Ⓖ崊䏓䵊":"","㋄Nj膮朲㌦냔ℋፋ":true}
// • …

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.

Last updated on by Nicolas DUBIEN