How to sum the values of a JavaScript object

Question

I d like to sum the values of an object   I m used to python where it would just be   sample      a   1    b   2    c  3    summed    sum sample itervalues           The following code works  but it s a lot of code   function obj values object      var results         for  var property in object      results push object property      return results     function list sum  list      return list reduce function previousValue  currentValue  index  array         return previousValue   currentValue           function object values sum  obj      return list sum obj values obj       var sample     a  1   b  2   c 3    var summed    list sum obj values a    var summed    object values sum a    Am i missing anything obvious  or is this just the way it is

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A ramda one liner   import    compose    sum   values    from  ramda   export const sumValues   compose sum  values     Use  const summed   sumValues    a   1    b   2    c  3

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Any reason you re not just using a simple for   in loop    var sample     a  1   b  2   c 3    var summed   0   for  var key in sample        summed    sample key        http   jsfiddle net vZhXs

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Use Lodash   x000D   x000D   import   from  Lodash   x000D    x000D   var object array     a  1  b  2  c  3    a  4  b  5  c  6    x000D    x000D   return   sumBy object array   c   x000D    x000D      return   gt  9 x000D   x000D   x000D

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I am a bit tardy to the party  however  if you require a more robust and flexible solution then here is my contribution  If you want to sum only a specific property in a nested object array combo  as well as perform other aggregate methods  then here is a little function I have been using on a React project   var aggregateProperty   function obj  property  aggregate  shallow  depth          return aggregated value of a specific property within an object  or array of objects         if   typeof obj      object   amp  amp  typeof obj      array       property            return             obj   JSON parse JSON stringify obj      an ugly way of copying the data object instead of pointing to its reference  so the original data remains unaffected      const validAggregates      sum    min    max    count         aggregate    validAggregates indexOf aggregate toLowerCase        -1   aggregate toLowerCase      sum      default to sum        default to false  if true  only searches  n  levels deep ignoring deeply nested data      if  shallow     true            shallow   2        else if  isNaN shallow     shallow  lt  2            shallow   false             if  isNaN depth             depth   1    how far down the rabbit hole have we travelled             var value     aggregate     min     aggregate     max     null   0       for  var prop in obj            if   obj hasOwnProperty prop                 continue                     var propValue   obj prop           var nested    typeof propValue      object     typeof propValue      array            if  nested                  the property is an object or an array              if  prop    property  amp  amp  aggregate     count                     value                               if  shallow     false    depth  lt  shallow                    propValue   aggregateProperty propValue  property  aggregate  shallow  depth 1     recursively aggregate nested objects and arrays               else                   continue    skip this property                                    aggregate the properties value based on the selected aggregation method         if   prop    property    nested   amp  amp  propValue                switch aggregate                    case  sum                       if   isNaN propValue                             value    propValue                                            break                  case  min                       if   propValue  lt  value      value                            value   propValue                                            break                  case  max                       if   propValue  gt  value      value                            value   propValue                                            break                  case  count                       if  propValue                            if  nested                                value    propValue                            else                               value                                                                        break                                     return value      It is recursive  non ES6  and it should work in most semi-modern browsers  You use it like this   const onlineCount   aggregateProperty this props contacts   online    count      Parameter breakdown   obj   either an object or an array property   the property within the nested objects arrays you wish to perform the aggregate method on aggregate   the aggregate method  sum  min  max  or count  shallow   can either be set to true false or a numeric value depth   should be left null or undefined  it is used to track the subsequent recursive callbacks   Shallow can be used to enhance performance if you know that you will not need to search deeply nested data  For instance if you had the following array                   id  1          otherData                   valueToBeTotaled                         id  2          otherData                   valueToBeTotaled                         id  3          otherData                   valueToBeTotaled                       If you wanted to avoid looping through the otherData property since the value you are going to be aggregating is not nested that deeply  you could set shallow to true

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x000D   x000D  let prices     x000D     apple   100  x000D     banana   300  x000D     orange   250 x000D     x000D   x000D  let sum   0  x000D  for  let price of Object values prices     x000D    sum    price  x000D    x000D   x000D  alert sum  x000D   x000D   x000D

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Now you can make use of reduce function and get the sum    x000D   x000D  const object1      a   1    b   2    c  3   x000D   x000D  console log Object values object1  reduce  a  b    gt  a   b  0    x000D   x000D   x000D

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I came across this solution from  jbabey while trying to solve a similar problem  With a little modification  I got it right  In my case  the object keys are numbers  489  and strings   489    Hence to solve this  each key is parse  The following code works   var array     nR   22   nH   7   totB    2761    nSR   16   htRb    91981   var parskey   0  for  var key in array        parskey   parseInt array key        sum    parskey     return sum

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Sum the object key value by parse Integer  Converting string format to integer and summing the values  x000D   x000D  var obj       pay  22    obj pay  console log obj pay   var x   parseInt obj pay   console log x   20   x000D   x000D   x000D

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A regular for loop is pretty concise   var total   0   for  var property in object        total    object property       You might have to add in object hasOwnProperty if you modified the prototype

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It can be as simple as that   const sumValues   obj   gt  Object values obj  reduce  a  b    gt  a   b     Quoting MDN      The Object values   method returns an array of a given object s own enumerable property values  in the same order as that provided by a for   in loop  the difference being that a for-in loop enumerates properties in the prototype chain as well     from Object values   on MDN     The reduce   method applies a function against an accumulator and each value of the array  from left-to-right  to reduce it to a single value    from Array prototype reduce   on MDN  You can use this function like that   sumValues  a  4  b  6  c  -5  d  0       gives 5     Note that this code uses some ECMAScript features which are not supported by some older browsers  like IE   You might need to use Babel to compile your code

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You could put it all in one function    x000D   x000D  function sum  obj     x000D    var sum   0  x000D    for  var el in obj     x000D      if  obj hasOwnProperty  el       x000D        sum    parseFloat  obj el     x000D        x000D      x000D    return sum  x000D    x000D       x000D  var sample     a  1   b  2   c 3    x000D  var summed   sum  sample    x000D  console log   sum    summed    x000D   x000D   x000D     For fun s sake here is another implementation using Object keys   and Array reduce    browser support should not be a big issue anymore     x000D   x000D  function sum obj    x000D    return Object keys obj  reduce  sum key   gt sum parseFloat obj key   0  0   x000D    x000D  let sample     a  1   b  2   c 3    x000D   x000D  console log  sum   sum sample      x000D   x000D   x000D    But this seems to be way slower  jsperf com

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Honestly  given our  modern times  I d go with a functional programming approach whenever possible  like so   const sumValues    obj    gt  Object keys obj  reduce  acc  value    gt  acc   obj value   0     Our accumulator acc  starting with a value of 0  is accumulating all looped values of our object  This has the added benefit of not depending on any internal or external variables  it s a constant function so it won t be accidentally overwritten    win for ES2015

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If you re using lodash you can do something like    sum   values    a   1    b   2    c  3

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We can iterate object using in keyword and can perform any arithmetic operation   x000D   x000D     input const sample          a   1       b   2       c   3        var let sum   0      object iteration for  key in sample          sum     sum      sample key         result console log  sum   gt    sum   x000D   x000D   x000D

[javascript] How to sum the values of a JavaScript object?

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