Sorting objects by property values

Question

How to implement the following scenario using Javascript only    Create a car object with properties  top speed  brand  etc   Sort a list of cars ordered by those properties

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With ES6 arrow functions it will be like this     Let s say we have these cars let cars       brand   Porsche   top speed  260        brand   Benz   top speed  110        brand   Fiat   top speed  90        brand   Aston Martin   top speed  70       Array prototype sort   can accept a comparator function  here I used arrow notation  but ordinary functions work the same    let sortedByBrand       cars  sort  first  second    gt  first brand  gt  second brand          brand   Aston Martin   top speed  70           brand   Benz   top speed  110           brand   Fiat   top speed  90           brand   Porsche   top speed  260       The above approach copies the contents of cars array into a new one and sorts it alphabetically based on brand names  Similarly  you can pass a different function   let sortedBySpeed      cars  sort  first  second    gt  first top speed  gt  second top speed         brand   Aston Martin   top speed  70          brand   Fiat   top speed  90          brand   Benz   top speed  110          brand   Porsche   top speed  260       If you don t mind mutating the orginal array cars sort comparatorFunction  will do the trick

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Example    This runs on cscript exe  on windows      define the Car class  function            makeClass - By John Resig  MIT Licensed         Allows either new User   or User   to be employed for construction      function makeClass            return function args               if   this instanceof arguments callee                     if   typeof this init     function                        this init apply  this   args  amp  amp  args callee    args   arguments                  else                 return new arguments callee  arguments                          Car   makeClass         Car prototype init   function make  model  price  topSpeed  weight            this make   make          this model   model          this price   price          this weight   weight          this topSpeed   topSpeed                    create a list of cars var autos         new Car  Chevy    Corvair   1800  88  2900       new Car  Buick    LeSabre   31000  138  3700       new Car  Toyota    Prius   24000  103  3200       new Car  Porsche    911   92000  155  3100       new Car  Mercedes    E500   67000  145  3800       new Car  VW    Passat   31000  135  3700         a list of sorting functions var sorters         byWeight   function a b            return  a weight - b weight              bySpeed   function a b            return  a topSpeed - b topSpeed              byPrice   function a b            return  a price - b price              byModelName   function a b            return   a model  lt  b model    -1     a model  gt  b model    1   0               byMake   function a b            return   a make  lt  b make    -1     a make  gt  b make    1   0              function say s   WScript Echo s     function show title        say   sorted by    title       for  var i 0  i  lt  autos length  i              say        autos i  model             say          autos sort sorters byWeight   show  Weight     autos sort sorters byModelName   show  Name     autos sort sorters byPrice   show  Price      You can also make a general sorter   var byProperty   function prop        return function a b            if  typeof a prop      number                 return  a prop  - b prop              else               return   a prop   lt  b prop     -1     a prop   gt  b prop     1   0                         autos sort byProperty  topSpeed     show  Top Speed

User · Answer

javascript has the sort function which can take another function as parameter - that second function is used to compare two elements   Example   cars                    name   Honda           speed  80                       name   BMW           speed  180                       name   Trabi           speed  40                       name   Ferrari           speed  200           cars sort function a  b         return a speed - b speed      for var i in cars      document writeln cars i  name     Trabi Honda BMW Ferrari    ok  from your comment i see that you re using the word  sort  in a wrong sense  In programming  sort  means  put things in a certain order   not  arrange things in groups   The latter is much simpler - this is just how you  sort  things in the real world   make two empty arrays   boxes   for each object in your list  check if it matches the criteria if yes  put it in the first  box  if no  put it in the second  box

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I have wrote this simple function for myself   function sortObj list  key        function compare a  b            a   a key           b   b key           var type    typeof a       string                         typeof b       string      string     number           var result          if  type      string   result   a localeCompare b           else result   a - b          return result            return list sort compare       for example you have list of cars    var cars    brand   audi   speed  240    brand   fiat   speed  190    var carsSortedByBrand   sortObj cars   brand    var carsSortedBySpeed   sortObj cars   speed

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Let us say we have to sort a list of objects in ascending order based on a particular property  in this example lets say we have to sort based on the  name  property  then below is the required code    var list Objects      name   Bob     name   Jay     name   Abhi     Console log list Objects          name   Bob     name   Jay     name   Abhi        list Objects sort function a b           return a  name   localeCompare b  name              Console log list Objects         name   Abhi     name   Bob     name   Jay

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A version of Cheeso solution with reverse sorting  I also removed the ternary expressions for lack of clarity  but this is personal taste    function prop  reverse      return function a  b        if  typeof a prop       number           return  a prop  - b prop               if  a prop   lt  b prop           return reverse   1   -1             if  a prop   gt  b prop           return reverse   -1   1             return 0

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Here s a short example  that creates and array of objects  and sorts numerically or alphabetically      Create Objects Array  var arrayCarObjects      brand   Honda          topSpeed  45    brand   Ford           topSpeed  6    brand   Toyota         topSpeed  240    brand   Chevrolet      topSpeed  120    brand   Ferrari        topSpeed  1000         Sort Objects Numerically  arrayCarObjects sort  a  b    gt   a topSpeed - b topSpeed        Sort Objects Alphabetically  arrayCarObjects sort  a  b    gt   a brand  gt  b brand    1   -1

[javascript] Sorting objects by property values

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