JavaScript equivalent to printf String Format

Question

I m looking for a good JavaScript equivalent of the C PHP printf   or for C  Java programmers  String Format    IFormatProvider for  NET    My basic requirement is a thousand separator format for numbers for now  but something that handles lots of combinations  including dates  would be good   I realize Microsoft s Ajax library provides a version of String Format    but we don t want the entire overhead of that framework

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I didn t see pyformat in the list so I thought I d throw it in   console log pyformat   The       jumped over the                         brown    fox    foobar                      console log pyformat  The  0   1  jumped over the  1                       brown    fox    foobar                      console log pyformat  The  color   animal  jumped over the  thing                          color   brown   animal   fox   thing   foobaz

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I started porting the Java String format  actually new Formatter   format    to javascript  The initial version is available at    https   github com RobAu javascript string format  You can simple add the javscript and call StringFormat format    2f    2 4    etc   Please note it is NOT finished yet  but feedback is welcome

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if you just need to format a string with  s specifier only function  sprintf message       const regexp   RegExp   s   g        let match      let index   1      while  match   regexp exec message       null            let replacement   arguments index           if  replacement                let messageToArray   message split                  messageToArray splice match index  regexp lastIndex - match index  replacement               message   messageToArray join                  index              else               break                       return message      sprintf  quot my name is  s  my age is  s quot    quot bob quot   50      my name is bob  my age is 50

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From ES6 on you could use template strings   let soMany   10  console log  This is   soMany  times easier         This is 10 times easier    Be aware that template strings are surrounded by backticks   instead of  single  quotes   For further information   https   developers google com web updates 2015 01 ES6-Template-Strings  https   developer mozilla org en-US docs Web JavaScript Reference template strings  Note  Check the mozilla-site to find a list of supported browsers

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I use this simple function   String prototype format   function         var formatted   this      for  var arg in arguments             formatted   formatted replace       arg        arguments arg              return formatted       That s very similar to string format     0  is dead  but  1  is alive   format  ASP    ASP NET

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I use a small library called String format for JavaScript which supports most of the format string capabilities  including format of numbers and dates   and uses the  NET syntax  The script itself is smaller than 4 kB  so it doesn t create much of overhead

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For those who like Node JS and its util format feature  I ve just extracted it out into its vanilla JavaScript form  with only functions that util format uses    exports        function isString arg        return typeof arg      string     function isNull arg        return arg     null    function isObject arg        return typeof arg      object   amp  amp  arg     null    function isBoolean arg        return typeof arg      boolean     function isUndefined arg        return arg     void 0    function stylizeNoColor str  styleType        return str    function stylizeWithColor str  styleType        var style   inspect styles styleType        if  style            return   u001b     inspect colors style  0     m    str                 u001b     inspect colors style  3     m         else           return str          function isFunction arg        return typeof arg      function     function isNumber arg        return typeof arg      number     function isSymbol arg        return typeof arg      symbol     function formatPrimitive ctx  value        if  isUndefined value           return ctx stylize  undefined    undefined        if  isString value             var simple          JSON stringify value  replace        g                       replace    g                          replace      g                       return ctx stylize simple   string              if  isNumber value                Format -0 as  -0   Strict equality won t distinguish 0 from -0             so instead we use the fact that 1   -0  lt  0 whereas 1   0  gt  0           if  value     0  amp  amp  1   value  lt  0              return ctx stylize  -0    number            return ctx stylize      value   number              if  isBoolean value           return ctx stylize      value   boolean           For some reason typeof null is  object   so special case here      if  isNull value           return ctx stylize  null    null           es6 symbol primitive     if  isSymbol value           return ctx stylize value toString     symbol      function arrayToHash array        var hash            array forEach function  val  idx            hash val    true               return hash    function objectToString o        return Object prototype toString call o     function isDate d        return isObject d   amp  amp  objectToString d        object Date      function isError e        return isObject e   amp  amp           objectToString e        object Error      e instanceof Error     function isRegExp re        return isObject re   amp  amp  objectToString re        object RegExp      function formatError value        return       Error prototype toString call value           function formatPrimitiveNoColor ctx  value        var stylize   ctx stylize      ctx stylize   stylizeNoColor      var str   formatPrimitive ctx  value       ctx stylize   stylize      return str    function isArray ar        return Array isArray ar     function hasOwnProperty obj  prop        return Object prototype hasOwnProperty call obj  prop     function formatProperty ctx  value  recurseTimes  visibleKeys  key  array        var name  str  desc      desc   Object getOwnPropertyDescriptor value  key      value  value key        if  desc get            if  desc set                str   ctx stylize   Getter Setter     special              else               str   ctx stylize   Getter     special                    else           if  desc set                str   ctx stylize   Setter     special                        if   hasOwnProperty visibleKeys  key             name         key                  if   str            if  ctx seen indexOf desc value   lt  0                if  isNull recurseTimes                     str   formatValue ctx  desc value  null                 else                   str   formatValue ctx  desc value  recurseTimes - 1                             if  str indexOf   n    gt  -1                    if  array                        str   str split   n   map function  line                            return        line                         join   n   substr 2                     else                       str     n    str split   n   map function  line                            return         line                         join   n                                              else               str   ctx stylize   Circular     special                        if  isUndefined name             if  array  amp  amp  key match    d                    return str                    name   JSON stringify      key           if  name match      a-zA-Z   a-zA-Z 0-9                       name   name substr 1  name length - 2               name   ctx stylize name   name              else               name   name replace    g                          replace      g                        replace          g                        replace       g                     name   ctx stylize name   string                         return name          str    function formatArray ctx  value  recurseTimes  visibleKeys  keys        var output           for  var i   0  l   value length  i  lt  l    i            if  hasOwnProperty value  String i                  output push formatProperty ctx  value  recurseTimes  visibleKeys                  String i   true              else               output push                          keys forEach function  key            if   key match    d                    output push formatProperty ctx  value  recurseTimes  visibleKeys                  key  true                          return output    function reduceToSingleString output  base  braces        var length   output reduce function  prev  cur            return prev   cur replace   u001b   d d m g      length   1         0        if  length  gt  60            return braces 0                 base               base     n                                    output join    n                                     braces 1              return braces 0    base         output join               braces 1     function formatValue ctx  value  recurseTimes           Provide a hook for user-specified inspect functions         Check that value is an object with an inspect function on it     if  ctx customInspect  amp  amp          value  amp  amp          isFunction value inspect   amp  amp                 Filter out the util module  it s inspect function is special         value inspect     exports inspect  amp  amp                 Also filter out any prototype objects using the circular check            value constructor  amp  amp  value constructor prototype     value             var ret   value inspect recurseTimes  ctx           if   isString ret                 ret   formatValue ctx  ret  recurseTimes                     return ret                Primitive types cannot have properties     var primitive   formatPrimitive ctx  value       if  primitive            return primitive                Look up the keys of the object      var keys   Object keys value       var visibleKeys   arrayToHash keys        if  ctx showHidden            keys   Object getOwnPropertyNames value                 This could be a boxed primitive  new String    etc    check valueOf          NOTE  Avoid calling  valueOf  on  Date  instance because it will return        a number which  when object has some additional user-stored  keys          will be printed out      var formatted      var raw   value      try              the  valueOf   call can fail for a multitude of reasons         if   isDate value               raw   value valueOf          catch  e               ignore               if  isString raw                for boxed Strings  we have to remove the 0-n indexed entries             since they just noisey up the output and are redundant         keys   keys filter function  key                return   key  gt   0  amp  amp  key  lt  raw length                             Some type of object without properties can be shortcutted      if  keys length     0            if  isFunction value                 var name   value name          value name                   return ctx stylize   Function    name         special                      if  isRegExp value                 return ctx stylize RegExp prototype toString call value    regexp                      if  isDate value                 return ctx stylize Date prototype toString call value    date                      if  isError value                 return formatError value                        now check the  raw  value to handle boxed primitives         if  isString raw                 formatted   formatPrimitiveNoColor ctx  raw               return ctx stylize   String      formatted         string                      if  isNumber raw                 formatted   formatPrimitiveNoColor ctx  raw               return ctx stylize   Number      formatted         number                      if  isBoolean raw                 formatted   formatPrimitiveNoColor ctx  raw               return ctx stylize   Boolean      formatted         boolean                         var base       array   false  braces                       Make Array say that they are Array     if  isArray value             array   true          braces                             Make functions say that they are functions     if  isFunction value             var n   value name          value name               base      Function    n                      Make RegExps say that they are RegExps     if  isRegExp value             base         RegExp prototype toString call value                 Make dates with properties first say the date     if  isDate value             base         Date prototype toUTCString call value                 Make error with message first say the error     if  isError value             base         formatError value                 Make boxed primitive Strings look like such     if  isString raw             formatted   formatPrimitiveNoColor ctx  raw           base           String      formatted                      Make boxed primitive Numbers look like such     if  isNumber raw             formatted   formatPrimitiveNoColor ctx  raw           base           Number      formatted                      Make boxed primitive Booleans look like such     if  isBoolean raw             formatted   formatPrimitiveNoColor ctx  raw           base           Boolean      formatted                   if  keys length     0  amp  amp    array    value length     0             return braces 0    base   braces 1              if  recurseTimes  lt  0            if  isRegExp value                 return ctx stylize RegExp prototype toString call value    regexp              else               return ctx stylize   Object     special                         ctx seen push value        var output      if  array            output   formatArray ctx  value  recurseTimes  visibleKeys  keys         else           output   keys map function  key                return formatProperty ctx  value  recurseTimes  visibleKeys  key  array                          ctx seen pop         return reduceToSingleString output  base  braces     function inspect obj  opts           default options     var ctx             seen              stylize  stylizeNoColor               legacy        if  arguments length  gt   3  ctx depth   arguments 2       if  arguments length  gt   4  ctx colors   arguments 3       if  isBoolean opts                legacy            ctx showHidden   opts        else if  opts               got an  options  object         exports  extend ctx  opts                set default options     if  isUndefined ctx showHidden   ctx showHidden   false      if  isUndefined ctx depth   ctx depth   2      if  isUndefined ctx colors   ctx colors   false      if  isUndefined ctx customInspect   ctx customInspect   true      if  ctx colors  ctx stylize   stylizeWithColor      return formatValue ctx  obj  ctx depth     exports inspect   inspect       http   en wikipedia org wiki ANSI escape code graphics inspect colors          bold    1  22        italic    3  23        underline    4  24        inverse    7  27        white    37  39        grey    90  39        black    30  39        blue    34  39        cyan    36  39        green    32  39        magenta    35  39        red    31  39        yellow    33  39         Don t use  blue  not visible on cmd exe inspect styles          special    cyan        number    yellow        boolean    yellow        undefined    grey        null    bold        string    green        symbol    green        date    magenta           name   intentionally not styling      regexp    red       var formatRegExp      sdj   g  exports format   function  f        if   isString f             var objects               for  var j   0  j  lt  arguments length  j                  objects push inspect arguments j                       return objects join                  var i   1      var args   arguments      var len   args length      var str   String f  replace formatRegExp  function  x            if  x           return              if  i  gt   len  return x          switch  x                case   s                   return String args i                  case   d                   return Number args i                  case   j                   try                       return JSON stringify args i                        catch                           return   Circular                                  default                  return x                        for  var x   args i   i  lt  len  x   args   i             if  isNull x      isObject x                 str          x            else               str          inspect x                       return str       Harvested from  https   github com joyent node blob master lib util js

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bobjs can do this   var sFormat    My name is  0  and I am  1  years old     var result   bob string formatString sFormat   Bob   29    console log result      output                    My name is Bob and I am 29 years old

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String prototype repeat   function n         return new Array   n  join this        String prototype pad   function requiredLength  paddingStr  paddingType            var n   requiredLength - this length        if  n            paddingType   paddingType   paddingType toLowerCase                 paddingStr   paddingStr                 paddingStr   paddingStr repeat  Math ceil n   paddingStr length    substr 0  n            if  paddingType     both                 n    2              return paddingStr substr  0  Math ceil n      this   paddingStr substr  0  Math floor n                           if  paddingType     left                 return paddingStr   this                     return this   paddingStr              return this                                printf              s   format        - gt                       1s   1s   s  format                               - gt                String prototype format   function         var i   0           params   arguments       return this replace               -     0        1-9  d          1-9  d       s d f   g  function match  sign  padding  width  precision  type            if  match                         return                          var v   params i              if  type     d                  v   Math round v                      else if  type     f                 v   v toFixed precision   precision   6                      if       test sign   amp  amp  v  gt  0                v         v                     v                 if  type     f   amp  amp  precision                v   v substr 0  precision                      if  width                v   v pad width  padding               padding 0           padding substr 1    padding   -  test sign     right     left                        return v                 this name              console log             name    template this                        String prototype template   function context        return this replace              g  function match  name            return context name

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For use with jQuery ajax   success functions   Pass only a single argument and string replace with the properties of that object as  propertyName    String prototype format   function          var formatted   this      for  var prop in arguments 0             var regexp   new RegExp         prop           gi            formatted   formatted replace regexp  arguments 0  prop              return formatted       Example   var userInfo     Email   Email  - Phone   Phone    format   Email   someone somewhere com   Phone   123-123-1234

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This is not an exact duplicate of sprintf  however  it is similar and more powerful  https   github com anywhichway stringformatter  Format expressions using this library take the form of embedded Javascript objects  e g   format  I have  number   currency       precision 2     50 2      will return  I have  50 20

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export function stringFormate  str  string     args  string           return args reduce  acc  curr  i    gt  acc replace new RegExp         i           g    curr   str

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Building on the previously suggested solutions      First  checks if it isn t implemented yet  if   String prototype format      String prototype format   function         var args   arguments      return this replace     d    g  function match  number           return typeof args number      undefined            args number            match                            0  is dead  but  1  is alive   0   2   format  ASP    ASP NET    outputs     ASP is dead  but ASP NET is alive  ASP  2      If you prefer not to modify String s prototype   if   String format      String format   function format        var args   Array prototype slice call arguments  1       return format replace     d    g  function match  number           return typeof args number      undefined            args number             match                          Gives you the much more familiar   String format   0  is dead  but  1  is alive   0   2     ASP    ASP NET     with the same result      ASP is dead  but ASP NET is alive  ASP  2

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For basic formatting    var template   jQuery validator format   0  is not a valid value    var result   template  abc

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Using Lodash you can get template functionality   Use the ES template literal delimiter as an  interpolate  delimiter  Disable support by replacing the  interpolate  delimiter   var compiled     template  hello    user       compiled    user    pebbles           gt   hello pebbles

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We can use a simple lightweight String Format string operation library for Typescript   String Format     var id   image GetId   String Format  image  0  jpg   id  output   image 2db5da20-1c5d-4f1a-8fd4-b41e34c8c5b5 jpg     String Format for specifiers   var value   String Format   0 L     APPLE      output  apple   value   String Format   0 U     apple       output  APPLE   value   String Format   0 d     2017-01-23 00 00      output  23 01 2017    value   String Format   0 s     21 03 2017 22 15 01     output  2017-03-21T22 15 01   value   String Format   0 n    1000000     output  1 000 000   value   String Format   0 00    1     output  01    String Format for Objects including specifiers   var fruit   new Fruit    fruit type    apple   fruit color    RED   fruit shippingDate   new Date 2018  1  1   fruit amount   10000   String Format  the  type U  is  color L  shipped on  shippingDate s  with an amount of  amount n    fruit      output  the APPLE is red shipped on 2018-01-01 with an amount of 10 000

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Here s a minimal implementation of sprintf in JavaScript  it only does   s  and   d   but I have left space for it to be extended  It is useless to the OP  but other people who stumble across this thread coming from Google might benefit from it   function sprintf         var args   arguments      string   args 0       i   1      return string replace        s d  g  function  m               m is the matched format  e g   s   d         var val   null          if  m 2                 val   m 2             else               val   args i                  A switch statement so that the formatter can be extended  Default is  s             switch  m                    case   d                       val   parseFloat val                       if  isNaN val                             val   0                                            break                            i                      return val              Example   alert sprintf  Latitude   s  Longitude   s  Count   d   41 847  -87 661   two        Expected output  Latitude  41 847  Longitude  -87 661  Count  0   In contrast with similar solutions in previous replies  this one does all substitutions in one go  so it will not replace parts of previously replaced values

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jsxt  Zippo  This option fits better   String prototype format   function         var formatted   this      for  var i   0  i  lt  arguments length  i              var regexp   new RegExp       i         gi            formatted   formatted replace regexp  arguments i              return formatted       With this option I can replace strings like these    The  0  is dead  Don  t code  0   Code  1  that is open source   format  ASP    PHP      With your code the second  0  wouldn t be replaced

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arg function           Qt stil arg      var scr     lt div id   1  class   2  gt  lt  div gt   arg  mydiv   arg  mydivClass        String prototype arg   function         var signIndex   this indexOf           var result   this      if  signIndex  gt  -1  amp  amp  arguments length  gt  0            var argNumber   this charAt signIndex   1           var  arg       argNumber          var argCount   this split  arg           for  var itemIndex   0  itemIndex  lt  argCount length  itemIndex                  result   result replace  arg  arguments 0                        return result

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Current JavaScript From ES6 on you could use template strings  let soMany   10  console log  This is   soMany  times easier         quot This is 10 times easier   See Kim s answer below for details   Older answer Try sprintf   for JavaScript   If you really want to do a simple format method on your own  don   t do the replacements successively but do them simultaneously  Because most of the other proposals that are mentioned fail when a replace string of previous replacement does also contain a format sequence like this   quot  0  1  quot  format  quot  1  quot    quot  0  quot    Normally you would expect the output to be  1  0  but the actual output is  1  1   So do a simultaneously replacement instead like in fearphage   s suggestion

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1 Zippo with the exception that the function body needs to be as below or otherwise it appends the current string on every iteration   String prototype format   function         var formatted   this      for  var arg in arguments            formatted   formatted replace       arg        arguments arg              return formatted

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I use this one   String prototype format   function         var newStr   this  i   0      while    s  test newStr           newStr   newStr replace   s   arguments i          return newStr      Then I call it     lt h1 gt  s lt  h1 gt  lt p gt  s lt  p gt   format  Header    Just a test

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One very slightly different version  the one I prefer  this one uses  xxx  tokens rather than  0  numbered arguments  this is much more self-documenting and suits localization much better    String prototype format   function tokens      var formatted   this    for  var token in tokens      if  tokens hasOwnProperty token         formatted   formatted replace RegExp       token         g    tokens token      return formatted       A variation would be     var formatted   l this     that calls an l   localization function first

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I needed a function which could format a price  given in cents  in a way preferred by the user  and the tricky part is that the format is specified by the user -- and I do not expect my users to understand printf-like syntax  or regexps  etc  My solution is somewhat similar to that used in Basic  so the user just marks with   places for digits  for example   simple format 1234567                        12 345 67  simple format 1234567                 pln    12 345 67 pln    I believe this is quite easy to understand by user  and quite easy to implement   function simple format integer format     var text         for var i format length i--        if format i               text    integer 10    text        integer Math floor integer 10         if integer  0           return format substr 0 i  replace               text               else        text   format i    text              return text

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There is  sprintf  for JavaScript which you can find at http   www webtoolkit info javascript-sprintf html

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I did not see the String format variant   String format   function  string        var args   Array prototype slice call arguments  1  arguments length       return string replace     d    g  function  match  number            return typeof args number      undefined    args number    match

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I m surprised no one used reduce  this is a native concise and powerful JavaScript function   ES6  EcmaScript2015    x000D   x000D  String prototype format   function     x000D    return     arguments  reduce  p c    gt  p replace   s  c   this   x000D     x000D   x000D  console log  Is that a  s or a  s     No  it  s  s   format  plane    bird    SOman     x000D   x000D   x000D     lt  ES6  function interpolate theString  argumentArray        var regex     s       var  r function p c  return p replace regex c        return argumentArray reduce  r  theString      interpolate   s   s and  s     Me    myself    I         Me  myself and I    How it works      reduce applies a function against an accumulator and each element in the array  from left to right  to reduce it to a single value     x000D   x000D  var  r  function p c  return p replace   s  c    x000D   x000D  console log  x000D      a    b    c   reduce  r     s     s  and   s        n   x000D     1  2  3  reduce  r    s  s  s       n   x000D      cool   1337   stuff   reduce  r    s  s  s   x000D     x000D   x000D   x000D

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Not the most recommended function in the world  but it works  If you need sprintf  just copy  amp  paste this same function and change return console log sb  to just return sb   x000D   x000D  printf   function s    args             a   arguments      al   a length           if  al  lt   1  return -2      if  al  gt   2  amp  amp  s toLowerCase   search    a-z       -1  return -1       sb   s      for  i   1  i  lt   al - 1  i              sb   sb replace    a-z    a i               return console log sb      var someString    Hello  s nIt s  s  s  s now  nThe day is  s n   printf someString   StackOverflowUser    5    48    PM    beautiful    x000D   x000D   x000D

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This is an implementation of https   stackoverflow com a 4673436 1258486 for CoffeeScript   https   gist github com eces 5669361  if String prototype format is undefined   String prototype format      - gt       arguments   arguments     this replace     d    g   match  number  - gt        if typeof  arguments number  isnt  undefined  then  arguments number  else match

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I want to share my solution for the  problem   I haven t re-invented the wheel but tries to find a solution based on what JavaScript already does  The advantage is  that you get all implicit conversions for free  Setting the prototype property   of String gives a very nice and compact syntax  see examples below   It is maybe not the most efficient way  but in most cases dealing with output it does not have to be super optimized   String form   function str  arr        var i   -1      function callback exp  p0  p1  p2  p3  p4            if  exp        return              if  arr   i    undefined  return undefined          exp    p2   parseInt p2 substr 1     undefined          var base   p3   parseInt p3 substr 1     undefined          var val          switch  p4                case  s   val   arr i   break              case  c   val   arr i  0   break              case  f   val   parseFloat arr i   toFixed exp   break              case  p   val   parseFloat arr i   toPrecision exp   break              case  e   val   parseFloat arr i   toExponential exp   break              case  x   val   parseInt arr i   toString base base 16   break              case  d   val   parseFloat parseInt arr i   base base 10  toPrecision exp   toFixed 0   break                    val   typeof val    object    JSON stringify val    val toString base           var sz   parseInt p1      padding size            var ch   p1  amp  amp  p1 0    0     0            isnull             while  val length lt sz  val   p0     undefined   val ch   ch val     isminus            return val            var regex      -   0  0-9         0-9         0-9      scfpexd    g      return str replace regex  callback      String prototype     function         return String form this  Array prototype slice call arguments        Here are a few examples   String format   s  s      This is a string   11    console log   s  s     This is a string   11   var arr      12 3   13 6    console log  Array   s    arr    var obj     test  test   id 12    console log  Object   s    obj    console log   c    Test    console log   5d    12           12  console log   05d    12        00012  console log   -5d    12        12     console log   5 2d    123          120  console log   5 2f    1 1         1 10  console log   10 2e    1 1           1 10e 0  console log   5 3p    1 12345         1 12  console log   5x    45054         affe  console log   20 2x     45054             1010111111111110  console log   6 2d     111              7  console log   6 16d     affe          45054

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If you are looking to handle the thousands separator  you should really use toLocaleString   from the JavaScript Number class since it will format the string for the user s region   The JavaScript Date class can format localized dates and times

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Number Formatting in JavaScript  I got to this question page hoping to find how to format numbers in JavaScript  without introducing yet another library   Here s what I ve found   Rounding floating-point numbers  The equivalent of sprintf    2f   num  in JavaScript seems to be num toFixed 2   which formats num to 2 decimal places  with rounding  but see  ars265 s comment about Math round below     12 345  toFixed 2      returns  12 35   rounding    12 3  toFixed 2      returns  12 30   zero padding    Exponential form  The equivalent of sprintf    2e   num  is num toExponential 2       33333  toExponential 2       3 33e 4    Hexadecimal and other bases  To print numbers in base B  try num toString B    JavaScript supports automatic conversion to and from bases 2 through 36  in addition  some browsers have limited support for base64 encoding     3735928559  toString 16      to base 16   deadbeef  parseInt  deadbeef   16      from base 16  3735928559   Reference Pages  Quick tutorial on JS number formatting  Mozilla reference page for toFixed    with links to toPrecision    toExponential    toLocaleString

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Format string by replacing placeholders with value from element with    corresponsing index in  replacementArray      Replaces are made simultaneously  so that replacement values like      1   will not mess up the function        Example 1        2   1   0      three    two    one    - gt   one two three        Example 2        0  1       1      0     - gt    1  0       function stringFormat formatString  replacementArray        return formatString replace               d     g     Matches placeholders  e g    1           function formatStringReplacer match  placeholderIndex                   Convert String to Number             placeholderIndex   Number placeholderIndex                   Make sure that index is within replacement array bounds             if  placeholderIndex  lt  0                    placeholderIndex  gt  replacementArray length - 1                                 return placeholderIndex                                Replace placeholder with value from replacement array             return replacementArray placeholderIndex

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x000D   x000D  String prototype format   function    x000D      var final   String this   x000D      for let i 0  i lt arguments length i     x000D          final   final replace   s  i 1    arguments i   x000D        x000D      return final       x000D    x000D   x000D  console log   hello  s2 how  s3 you  s1   format  hi    hello    how     x000D   lt h1 id  text  gt  x000D      x000D   lt  h1 gt  x000D   x000D   x000D

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Very elegant   String prototype format   function         var args   arguments      return this replace                d     g  function  curlyBrack  index            return   curlyBrack                    curlyBrack                  args index                    Usage    0  1   format   1      0      Credit goes to  broken link  https   gist github com 0i0 1519811

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You can use this function              String prototype format   function  args                var str   this              return str replace String prototype format regex  function item                    var intVal   parseInt item substring 1  item length - 1                    var replace                  if  intVal  gt   0                        replace   args intVal                     else if  intVal     -1                        replace                          else if  intVal     -2                        replace                          else                       replace                                         return replace                                     String prototype format regex   new RegExp   -  0-9       g                Sample usage          var str    She  1   0  2  by the  0  3    -1     -2            str   str format   sea    sells    shells    shore             alert str

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This one works with  0    1  and      String prototype format   function format                                                                                                                      var msg   this    for var i in arguments      msg   msg replace        arguments i   replace new RegExp       i        g   arguments i      return msg

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another suggestion is you use the string template   const getPathDadosCidades    id  string    gt     clientes   id    const getPathDadosCidades    id  string  role  string    gt     clientes   id  roles   role

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I have a solution very close to Peter s  but it deals with number and object case   if   String prototype format      String prototype format   function         var args      args   arguments      if  args length     1  amp  amp  args 0      null  amp  amp  typeof args 0       object           args   args 0             return this replace            g  function match  key          return  typeof args key       undefined    args key    match                    Maybe it could be even better to deal with the all deeps cases  but for my needs this is just fine    This is an example from  name   format  name  Blaine      This is an example from  0   format  Blaine      PS  This function is very cool if you are using translations in templates frameworks like AngularJS    lt h1 gt      hello-message  translate  format user     lt h1 gt   lt h1 gt      hello-by-name  translate  format  user   user name    You       lt h1 gt    Where the en json is something like         hello-message    Hello  name   welcome         hello-by-name    Hello  0   welcome

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Just in case someone needs a function to prevent polluting global scope  here is the function that does the same     function  format  str  arr        return str replace     d    g  function  match  number          return typeof arr number      undefined    arr number    match

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Adding to zippoxer s answer  I use this function   String prototype format   function          var a   this  b      for  b in arguments            a   a replace    a-z    arguments b              return a     Make chainable     var s    Hello  s The magic number is  d    s format  world    12      Hello World  The magic number is 12    I also have a non-prototype version which I use more often for its Java-like syntax   function format         var a  b  c      a   arguments 0       b           for c   1  c  lt  arguments length  c             b push arguments c              for  c in b            a   a replace    a-z    b c              return a    format   d ducks  55  s   12   cats       12 ducks  55 cats   ES 2015 update  All the cool new stuff in ES 2015 makes this a lot easier   function format fmt     args       return fmt          split                reduce  aggregate  chunk  i    gt              aggregate   chunk    args i                  format  Hello     I ate    apples today     World   44       Hello World  I ate 44 apples today     I figured that since this  like the older ones  doesn t actually parse the letters  it might as well just use a single token     This has the benefit of being obvious and not making it difficult to use a single    However  if you need    for some reason  you would need to replace it with itself   format  I love percentage signs                  I love percentage signs

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There is also Globalize format in the jQuery Globalize project  the official globalization service for jQuery UI  IT s nice when you need culture-aware formatting

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JavaScript programmers can use String prototype sprintf at https   github com ildar-shaimordanov jsxt blob master js String js  Below is example   var d   new Date    var dateStr     02d  02d  02d  sprintf      d getHours         d getMinutes         d getSeconds

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sprintf   function analog in JavaScript as Vue filter and String prototype format   extension         Returns a formatted string         param template     param values     return string     String format   function  template     values        let i   -1       function callback exp  p0  p1  p2  p3  p4            if  exp           return              if  values   i      undefined  return undefined           exp   p2   parseInt p2 substr 1     undefined           let base   p3   parseInt p3 substr 1     undefined          let val           switch  p4                case  s   val   values i   break              case  c   val   values i  0   break              case  f   val   parseFloat values i   toFixed exp   break              case  p   val   parseFloat values i   toPrecision exp   break              case  e   val   parseFloat values i   toExponential exp   break              case  x   val   parseInt values i   toString base   base   16   break              case  d   val   parseFloat parseInt values i   base   base   10  toPrecision exp   toFixed 0   break                    val   typeof  val      object    JSON stringify val    val toString base           let sz   parseInt p1      padding size            let ch   p1  amp  amp  p1 0       0     0            isnull              while  val length  lt  sz  val   p0     undefined   val   ch   ch   val     isminus              return val             let regex      -   0  0-9         0-9         0-9      scfpexd    g       return template replace regex  callback      String prototype format   function         return String format this     arguments      const StringFormat         install   Vue  options    gt            Vue filter  format   function                  return String format    arguments                          export default StringFormat   Original answer  JavaScript equivalent to printf String Format

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It s funny because Stack  Overflow actually has their own formatting function for the String prototype called formatUnicorn  Try it  Go into the console and type something like   quot Hello   name   are you feeling  adjective   quot  formatUnicorn  name  quot Gabriel quot   adjective   quot OK quot       You get this output  Hello  Gabriel  are you feeling OK  You can use objects  arrays  and strings as arguments  I got its code and reworked it to produce a new version of String prototype format  String prototype formatUnicorn   String prototype formatUnicorn    function           quot use strict quot       var str   this toString        if  arguments length            var t   typeof arguments 0           var key          var args     quot string quot      t     quot number quot      t                Array prototype slice call arguments                arguments 0            for  key in args                str   str replace new RegExp  quot     quot    key    quot     quot    quot gi quot    args key                         return str      Note the clever Array prototype slice call arguments  call -- that means if you throw in arguments that are strings or numbers  not a single JSON-style object  you get C  s String Format behavior almost exactly   quot a 0 bcd 1 ef quot  formatUnicorn  quot FOO quot    quot BAR quot       yields  quot aFOObcdBARef quot   That s because Array s slice will force whatever s in arguments into an Array  whether it was originally or not  and the key will be the index  0  1  2     of each array element coerced into a string  eg   quot 0 quot   so  quot    0    quot  for your first regexp pattern   Neat

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I have a slightly longer formatter for JavaScript here       You can do formatting several ways    String format input  args0  arg1       String format input  obj   literal  format arg0  arg1        literal  format obj    Also  if you have say a ObjectBase prototype format  such as with DateJS  it will use that   Examples     var input    numbered args   0 - 1 - 2 - 3     console log String format input   first   2  new Date        Outputs  numbered args  first-2-Thu May 31 2012   Time - 3     console log input format  first   2  new Date        Outputs  numbered args first-2-Thu May 31 2012   Time - 3     console log input format       object properties   first - second - third yyyy-MM-dd - fourth                    first   first            second  2           third  new Date     assumes Date prototype format method             Outputs  object properties  first-2-2012-05-31- 3      I ve also aliased with  asFormat and have some detection in place in case there s already a string format  such as with MS Ajax Toolkit  I hate that library

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The PHPJS project has written JavaScript implementations for many of PHP s functions  Since PHP s sprintf   function is basically the same as C s printf    their JavaScript implementation of it should satisfy your needs

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In typescript create a file named format ts and import it whatever you need to use formatting      contents of format ts  interface String     format    args  any     string     if   String prototype format      String prototype format   function         let a   this      let b  any         tslint disable-next-line  forin     for  b in arguments          a   a replace    a-z    arguments b              return a           To format string use this code   import    format    console log  Hello   s   format  World       Example   x000D   x000D  String prototype format   function     x000D    let a   this  x000D    let b  x000D    for  b in arguments    x000D      a   a replace    a-z    arguments b    x000D      x000D    return a  x000D     x000D   x000D  console log  Hello   s   format  World     x000D   x000D   x000D

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I ll add my own discoveries which I ve found since I asked    number format  for thousand separator currency formatting  sprintf  same author as above    Sadly it seems sprintf doesn t handle thousand separator formatting like  NET s string format

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For Node js users there is util format which has printf-like functionality   util format   s world    Hello

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With sprintf js in place - one can make a nifty little format-thingy   String prototype format   function        var  args   arguments      Array prototype unshift apply  args  this       return sprintf apply undefined  args          this gives you     1 s   2 s   format  1    0       1  0

[javascript] JavaScript equivalent to printf/String.Format

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