What s the best way to convert a number to a string in JavaScript

Question

What s the  best  way to convert a number to a string  in terms of speed advantage  clarity advantage  memory advantage  etc     Some examples    String n  n toString      n n

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We can also use the String constructor  According to this benchmark it s the fastest way to convert a Number to String in Firefox 58 even though it s slower than      num in the popular browser Google Chrome

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Method toFixed   will also solves the purpose   var n   8 434332  n toFixed 2      8 43

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JavaScript s parser tries to parse   the dot notation on a number as a floating point literal    2  toString       the second point is correctly recognized 2  toString       note the space left to the dot  2  toString       2 is evaluated first   Source

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Explicit conversions are very clear to someone that s new to the language   Using type coercion  as others have suggested  leads to ambiguity if a developer is not aware of the coercion rules   Ultimately developer time is more costly than CPU time  so I d optimize for the former at the cost of the latter   That being said  in this case the difference is likely negligible  but if not I m sure there are some decent JavaScript compressors that will optimize this sort of thing   So  for the above reasons I d go with  n toString   or String n    String n  is probably a better choice because it won t fail if n is null or undefined

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With number literals  the dot for accessing a property must be distinguished from the decimal dot  This leaves you with the following options if you want to invoke to String   on the number literal 123   123  toString   123  toString      space before the dot 123 0 toString    123  toString

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You can call Number object and then call toString     Number call null  n  toString    You may use this trick for another javascript native objects

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If I had to take everything into consideration  I will suggest following     var myint   1  var mystring   myint         or int to string   myint   myint        IMHO  its the fastest way to convert to string  Correct me if I am wrong

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I m going to re-edit this with more data when I have time to  for right now this is fine     Test in nodejs v8 11 2  2018 06 06   x000D   x000D  let i 0  x000D      console time  test1   x000D      for  i lt 10000000 i i 1   x000D       const string        1234  x000D        x000D      console timeEnd  test1   x000D       x000D      i 0  x000D      console time  test1 1   x000D      for  i lt 10000000 i i 1   x000D       const string        1234  x000D        x000D      console timeEnd  test1 1   x000D       x000D      i 0  x000D      console time  test1 2   x000D      for  i lt 10000000 i i 1   x000D       const string        1234  x000D        x000D      console timeEnd  test1 2   x000D       x000D      i 0  x000D      console time  test1 3   x000D      for  i lt 10000000 i i 1   x000D       const string   1234        x000D        x000D      console timeEnd  test1 3   x000D       x000D       x000D      i 0  x000D      console time  test2   x000D      for  i lt 10000000 i i 1   x000D       const string    1234  toString    x000D        x000D      console timeEnd  test2   x000D       x000D       x000D      i 0  x000D      console time  test3   x000D      for  i lt 10000000 i i 1   x000D       const string   String 1234   x000D        x000D      console timeEnd  test3   x000D       x000D       x000D      i 0  x000D      console time  test4   x000D      for  i lt 10000000 i i 1   x000D       const string      1234    x000D        x000D      console timeEnd  test4   x000D       x000D      i 0  x000D      console time  test5   x000D      for  i lt 10000000 i i 1   x000D       const string   1234  toString    x000D        x000D      console timeEnd  test5   x000D       x000D      i 0  x000D      console time  test6   x000D      for  i lt 10000000 i i 1   x000D       const string   1234  toString    x000D        x000D      console timeEnd  test6   x000D   x000D   x000D    output   test1  72 268ms test1 1  61 086ms test1 2  66 854ms test1 3  63 698ms test2  207 912ms test3  81 987ms test4  59 752ms test5  213 136ms test6  204 869ms

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Other answers already covered other options  but I prefer this one   s      n     Short  succinct  already used in many other places  if you re using a modern framework   ES version  so it s a safe bet any programmer will understand it   Not that it  usually  matters much  but it also seems to be among the fastest compared to other methods

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If you are curious as to which is the most performant check this out where I compare all the different Number -  String conversions   Looks like 2    or 2    are the fastest   https   jsperf com int-2-string

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Tongue-in-cheek obviously   var harshNum   108     split call harshNum     join        Or in ES6 you could simply use template strings   var harshNum   108     harshNum

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I used https   jsperf com to create a test case for the following cases   number         number   String number  number toString     https   jsperf com number-string-conversion-speed-comparison  As of 24th of July  2018 the results say that number      is the fastest in Chrome  in Firefox that ties with template string literals   Both String number   and number toString   are around 95  slower than the fastest option

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Just come across this recently  method 3 and 4 are not appropriate because how the strings are copied and then put together  For a small program this problem is insignificant  but for any real web application this action where we have to deal with frequency string manipulations can affects the performance and readability    Here is the link the read

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toString   is the built-in typecasting function  I m no expert to that details but whenever we compare built-in type casting verse explicit methodologies  built-in workarounds always preferred

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If you need to format the result to a specific number of decimal places  for example to represent currency  you need something like the toFixed   method   number toFixed   digits      digits is the number of digits to display after the decimal place

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The only valid solution for almost all possible existing and future cases  input is number  null  undefined  Symbol  anything else  is String x   Do not use 3 ways for simple operation  basing on value type assumptions  like  here I convert definitely number to string and here definitely boolean to string    Explanation   String x  handles nulls  undefined  Symbols   anything  and calls  toString   for objects        x calls  valueOf   on x  casting to number   throws on Symbols  can provide implementation dependent results   x toString   throws on nulls and undefined   Note  String x  will still fail on prototype-less objects like Object create null    If you don t like strings like  Hello  undefined  or want to support prototype-less objects  use the following type conversion function          Safely casts any value to string  Null and undefined are converted to         param      value     return  string      function string  str      return value    null         typeof value      object   amp  amp   value toString     object     String value

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I like the first two since they re easier to read  I tend to use String n  but it is just a matter of style than anything else   That is unless you have a line as  var n   5  console log   the number is      n     which is very self explanatory

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like this   var foo   45  var bar        foo    Actually  even though I typically do it like this for simple convenience  over 1 000s of iterations it appears for raw speed there is an advantage for  toString    See Performance tests here  not by me  but found when I went to write my own   http   jsben ch   ghQYR  Fastest based on the JSPerf test above  str   num toString     It should be noted that the difference in speed is not overly significant when you consider that it can do the conversion any way 1 Million times in 0 1 seconds   Update  The speed seems to differ greatly by browser   In Chrome num      seems to be fastest based on this test http   jsben ch   ghQYR  Update 2  Again based on my test above it should be noted that Firefox 20 0 1 executes the  toString   about 100 times slower than the      num sample

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It seems similar results when using node js  I ran this script   let bar  let foo     45   foo     console time  string concat testing    for  let i   0  i  lt  10000000  i          bar        foo    console timeEnd  string concat testing      console time  string obj testing    for  let i   0  i  lt  10000000  i          bar   String foo     console timeEnd  string obj testing     console time  string both    for  let i   0  i  lt  10000000  i          bar        foo         console timeEnd  string both      and got the following results     node testing js string concat testing  2802 542ms string obj testing  3374 530ms string both  2660 023ms   Similar times each time I ran it

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In my opinion n toString   takes the prize for its clarity  and I don t think it carries any extra overhead

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The below are the methods to convert a Integer to String in JS The methods are arranged in the decreasing order of performance   The performance test results are given by  DarckBlezzer in his answer  var num   1  Method 1  num      num    Method 2  num   num       Method 3  num   String num   Method 4  num   num toString    Note  You can t directly call toString   on a number  2 toString   will throw Uncaught SyntaxError  Invalid or unexpected token

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The simplest way to convert any variable to a string is to add an empty string to that variable     5 41            Result  the string  5 41  Math PI         Result  the string  3 141592653589793

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I think it depends on the situation but anyway you can use the  toString   method as it is very clear to understand

[javascript] What's the best way to convert a number to a string in JavaScript?

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