[{"data":1,"prerenderedAt":367},["ShallowReactive",2],{"term-n\u002Fnan":3,"related-n\u002Fnan":350},{"id":4,"title":5,"acronym":6,"body":7,"category":330,"description":331,"difficulty":332,"extension":333,"letter":334,"meta":335,"navigation":182,"path":336,"related":337,"seo":343,"sitemap":344,"stem":347,"subcategory":348,"__hash__":349},"terms\u002Fterms\u002Fn\u002Fnan.md","NaN","Not a Number",{"type":8,"value":9,"toc":324},"minimark",[10,15,19,23,26,30,313,317,320],[11,12,14],"h2",{"id":13},"eli5-the-vibe-check","ELI5 — The Vibe Check",[16,17,18],"p",{},"NaN means 'Not a Number' — it is what JavaScript gives you when math goes wrong in a weird way. Try to parse a word as a number and you get NaN. The bizarre thing: NaN is technically of type 'number' and does not equal itself. It is JavaScript's way of saying 'this math made no sense'.",[11,20,22],{"id":21},"real-talk","Real Talk",[16,24,25],{},"NaN is a special numeric value defined by the IEEE 754 floating-point standard representing an undefined or unrepresentable mathematical result. In JavaScript, NaN arises from invalid number operations (parsing non-numeric strings, dividing 0\u002F0, Math.sqrt(-1)). Crucially, NaN !== NaN by specification — use Number.isNaN() to check for it, not strict equality.",[11,27,29],{"id":28},"show-me-the-code","Show Me The Code",[31,32,37],"pre",{"className":33,"code":34,"language":35,"meta":36,"style":36},"language-javascript shiki shiki-themes material-theme-lighter material-theme material-theme-palenight","\u002F\u002F How NaN appears:\nconsole.log(parseInt('hello'));    \u002F\u002F NaN\nconsole.log(0 \u002F 0);               \u002F\u002F NaN\nconsole.log(Math.sqrt(-1));       \u002F\u002F NaN\nconsole.log(undefined + 1);       \u002F\u002F NaN\n\n\u002F\u002F The weird part:\nconsole.log(NaN === NaN);         \u002F\u002F false! NaN never equals itself\n\n\u002F\u002F Correct way to check:\nconsole.log(Number.isNaN(NaN));   \u002F\u002F true\nconsole.log(isNaN('hello'));      \u002F\u002F true (coerces first — beware)\nconsole.log(Number.isNaN('hello')); \u002F\u002F false (strict, no coercion)\n","javascript","",[38,39,40,49,90,119,151,177,184,190,216,221,227,255,283],"code",{"__ignoreMap":36},[41,42,45],"span",{"class":43,"line":44},"line",1,[41,46,48],{"class":47},"sHwdD","\u002F\u002F How NaN appears:\n",[41,50,52,56,60,64,67,70,72,75,79,81,84,87],{"class":43,"line":51},2,[41,53,55],{"class":54},"sTEyZ","console",[41,57,59],{"class":58},"sMK4o",".",[41,61,63],{"class":62},"s2Zo4","log",[41,65,66],{"class":54},"(",[41,68,69],{"class":62},"parseInt",[41,71,66],{"class":54},[41,73,74],{"class":58},"'",[41,76,78],{"class":77},"sfazB","hello",[41,80,74],{"class":58},[41,82,83],{"class":54},"))",[41,85,86],{"class":58},";",[41,88,89],{"class":47},"    \u002F\u002F NaN\n",[41,91,93,95,97,99,101,105,108,111,114,116],{"class":43,"line":92},3,[41,94,55],{"class":54},[41,96,59],{"class":58},[41,98,63],{"class":62},[41,100,66],{"class":54},[41,102,104],{"class":103},"sbssI","0",[41,106,107],{"class":58}," \u002F",[41,109,110],{"class":103}," 0",[41,112,113],{"class":54},")",[41,115,86],{"class":58},[41,117,118],{"class":47},"               \u002F\u002F NaN\n",[41,120,122,124,126,128,131,133,136,138,141,144,146,148],{"class":43,"line":121},4,[41,123,55],{"class":54},[41,125,59],{"class":58},[41,127,63],{"class":62},[41,129,130],{"class":54},"(Math",[41,132,59],{"class":58},[41,134,135],{"class":62},"sqrt",[41,137,66],{"class":54},[41,139,140],{"class":58},"-",[41,142,143],{"class":103},"1",[41,145,83],{"class":54},[41,147,86],{"class":58},[41,149,150],{"class":47},"       \u002F\u002F NaN\n",[41,152,154,156,158,160,162,165,168,171,173,175],{"class":43,"line":153},5,[41,155,55],{"class":54},[41,157,59],{"class":58},[41,159,63],{"class":62},[41,161,66],{"class":54},[41,163,164],{"class":58},"undefined",[41,166,167],{"class":58}," +",[41,169,170],{"class":103}," 1",[41,172,113],{"class":54},[41,174,86],{"class":58},[41,176,150],{"class":47},[41,178,180],{"class":43,"line":179},6,[41,181,183],{"emptyLinePlaceholder":182},true,"\n",[41,185,187],{"class":43,"line":186},7,[41,188,189],{"class":47},"\u002F\u002F The weird part:\n",[41,191,193,195,197,199,201,203,206,209,211,213],{"class":43,"line":192},8,[41,194,55],{"class":54},[41,196,59],{"class":58},[41,198,63],{"class":62},[41,200,66],{"class":54},[41,202,5],{"class":58},[41,204,205],{"class":58}," ===",[41,207,208],{"class":58}," NaN",[41,210,113],{"class":54},[41,212,86],{"class":58},[41,214,215],{"class":47},"         \u002F\u002F false! NaN never equals itself\n",[41,217,219],{"class":43,"line":218},9,[41,220,183],{"emptyLinePlaceholder":182},[41,222,224],{"class":43,"line":223},10,[41,225,226],{"class":47},"\u002F\u002F Correct way to check:\n",[41,228,230,232,234,236,239,241,244,246,248,250,252],{"class":43,"line":229},11,[41,231,55],{"class":54},[41,233,59],{"class":58},[41,235,63],{"class":62},[41,237,238],{"class":54},"(Number",[41,240,59],{"class":58},[41,242,243],{"class":62},"isNaN",[41,245,66],{"class":54},[41,247,5],{"class":58},[41,249,83],{"class":54},[41,251,86],{"class":58},[41,253,254],{"class":47},"   \u002F\u002F true\n",[41,256,258,260,262,264,266,268,270,272,274,276,278,280],{"class":43,"line":257},12,[41,259,55],{"class":54},[41,261,59],{"class":58},[41,263,63],{"class":62},[41,265,66],{"class":54},[41,267,243],{"class":62},[41,269,66],{"class":54},[41,271,74],{"class":58},[41,273,78],{"class":77},[41,275,74],{"class":58},[41,277,83],{"class":54},[41,279,86],{"class":58},[41,281,282],{"class":47},"      \u002F\u002F true (coerces first — beware)\n",[41,284,286,288,290,292,294,296,298,300,302,304,306,308,310],{"class":43,"line":285},13,[41,287,55],{"class":54},[41,289,59],{"class":58},[41,291,63],{"class":62},[41,293,238],{"class":54},[41,295,59],{"class":58},[41,297,243],{"class":62},[41,299,66],{"class":54},[41,301,74],{"class":58},[41,303,78],{"class":77},[41,305,74],{"class":58},[41,307,83],{"class":54},[41,309,86],{"class":58},[41,311,312],{"class":47}," \u002F\u002F false (strict, no coercion)\n",[11,314,316],{"id":315},"when-youll-hear-this","When You'll Hear This",[16,318,319],{},"\"The calculation returns NaN — you're probably parsing a string as a number.\" \u002F \"Use Number.isNaN(), not isNaN() — they behave differently.\"",[321,322,323],"style",{},"html pre.shiki code .sHwdD, html code.shiki .sHwdD{--shiki-light:#90A4AE;--shiki-light-font-style:italic;--shiki-default:#546E7A;--shiki-default-font-style:italic;--shiki-dark:#676E95;--shiki-dark-font-style:italic}html pre.shiki code .sTEyZ, html code.shiki .sTEyZ{--shiki-light:#90A4AE;--shiki-default:#EEFFFF;--shiki-dark:#BABED8}html pre.shiki code .sMK4o, html code.shiki .sMK4o{--shiki-light:#39ADB5;--shiki-default:#89DDFF;--shiki-dark:#89DDFF}html pre.shiki code .s2Zo4, html code.shiki .s2Zo4{--shiki-light:#6182B8;--shiki-default:#82AAFF;--shiki-dark:#82AAFF}html pre.shiki code .sfazB, html code.shiki .sfazB{--shiki-light:#91B859;--shiki-default:#C3E88D;--shiki-dark:#C3E88D}html pre.shiki code .sbssI, html code.shiki .sbssI{--shiki-light:#F76D47;--shiki-default:#F78C6C;--shiki-dark:#F78C6C}html .light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html.light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}",{"title":36,"searchDepth":51,"depth":51,"links":325},[326,327,328,329],{"id":13,"depth":51,"text":14},{"id":21,"depth":51,"text":22},{"id":28,"depth":51,"text":29},{"id":315,"depth":51,"text":316},"general","NaN means 'Not a Number' — it is what JavaScript gives you when math goes wrong in a weird way. Try to parse a word as a number and you get NaN.","beginner","md","n",{},"\u002Fterms\u002Fn\u002Fnan",[338,339,340,341,342],"Null","Undefined","Float","Type","JavaScript",{"title":5,"description":331},{"changefreq":345,"priority":346},"weekly",0.7,"terms\u002Fn\u002Fnan",null,"UeKhBMOHClH3QpdV_DdafSKv92IhvJnffkpKSKbQMVk",[351,354,358,361,364],{"title":340,"path":352,"acronym":348,"category":330,"difficulty":332,"description":353},"\u002Fterms\u002Ff\u002Ffloat","A float is a number with a decimal point — 3.14, 1.5, -0.001. The name comes from 'floating point' because the decimal point can be anywhere.",{"title":342,"path":355,"acronym":348,"category":356,"difficulty":332,"description":357},"\u002Fterms\u002Fj\u002Fjavascript","frontend","JavaScript is what makes websites actually DO stuff. HTML is the bones, CSS is the skin, and JavaScript is the muscles and brain.",{"title":338,"path":359,"acronym":348,"category":330,"difficulty":332,"description":360},"\u002Fterms\u002Fn\u002Fnull","Null means 'intentionally nothing' — a programmer chose to say 'there is no value here'. It is a deliberate absence.",{"title":341,"path":362,"acronym":348,"category":330,"difficulty":332,"description":363},"\u002Fterms\u002Ft\u002Ftype","A type tells the computer what kind of thing a value is — is it a number, text, true\u002Ffalse, or a list?",{"title":339,"path":365,"acronym":348,"category":330,"difficulty":332,"description":366},"\u002Fterms\u002Fu\u002Fundefined","Undefined in JavaScript means a variable exists but has never been given a value.",1776518296937]