OrderBy pipe issue

Question

I m not able to translate this code from Angualr 1 to Angular 2     ng-repeat  todo in todos   orderBy   completed     This is what i ve done following the Thierry Templier s answer   Component  template      ngFor   todo of todos   sort    Component code      Component       selector   my-app       templateUrl     app todo-list component html       providers   TodoService       pipes    TodosSortPipe         Pipe code     import   Pipe   from  angular2 core   import  Todo  from    todo     Pipe     name   sort     export class TodosSortPipe     transform array  Array lt Todo gt   args  string   Array lt Todo gt        array sort  a  any  b  any    gt          if  a  lt  b            return -1          else if  a  gt  b            return 1          else           return 0                      return array          I m trying to sort an array of Todos  ordered by the property completed  First todo completed   false and then the todo complete   true   I don t understand very well the transform method and how to pass the arguments in that method and in the sort method   What is the args  string argument  What are a and b and where they come from

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I modified  Thierry Templier s response so the pipe can sort custom objects in angular 4   import   Pipe  PipeTransform   from   angular core     Pipe     name   sort     export class ArraySortPipe  implements PipeTransform     transform array  any  field  string   any         if   Array isArray array           return            array sort  a  any  b  any    gt          if  a field   lt  b field             return -1          else if  a field   gt  b field             return 1          else           return 0                      return array          And to use it    ngFor  let myObj of myArr   sort  fieldName     Hopefully this helps someone

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In the current version of Angular2  orderBy and ArraySort pipes are not supported  You need to write use some custom pipes for this

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Component template  todos  sort     property       asc desc     Pipe code   import   Pipe PipeTransform    from  angular core   import  Todo  from    todo     Pipe     name   sort     export class TodosSortPipe implements PipeTransform     transform array  Array lt Todo gt   args  string   Array lt Todo gt        array sort  a  any  b  any    gt          if  a  lt  b            return -1          else if  a  gt  b            return 1          else   enter code here          return 0                      return array

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Recommend u use lodash with angular  then your pipe will be next   import  Pipe  PipeTransform  from   angular core   import   as   from  lodash   Pipe       name   orderBy     export class OrderByPipe implements PipeTransform        transform array  Array lt any gt   args   any   any           return   sortBy array   args               and use it in html like   ngFor     todo of todos   orderBy  completed     and don t forget add Pipe to your module   NgModule                declarations   OrderByPipe

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Please see https   angular io guide pipes appendix-no-filterpipe-or-orderbypipe for the full discussion  This quote is most relevant  Basically  for large scale apps that should be minified aggressively the filtering and sorting logic should move to the component itself       Some of us may not care to minify this aggressively  That s our   choice  But the Angular product should not prevent someone else from   minifying aggressively  Therefore  the Angular team decided that   everything shipped in Angular will minify safely       The Angular team and many experienced Angular developers strongly   recommend that you move filtering and sorting logic into the component   itself  The component can expose a filteredHeroes or sortedHeroes   property and take control over when and how often to execute the   supporting logic  Any capabilities that you would have put in a pipe   and shared across the app can be written in a filtering sorting   service and injected into the component

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lt  -- const cars   Audi   Merc   BMW   Volvo   Tesla   -- gt    lt ul gt     lt li  ngFor  let car of cars  gt   car   lt  li gt   lt  ul gt         ngFor  let c of oneDimArray   sortBy  asc     ngFor  let c of arrayOfObjects   sortBy  asc   propertyName      import   Pipe  PipeTransform   from   angular core   import   orderBy   from  lodash     Pipe   name   sortBy     export class SortByPipe implements PipeTransform      transform value  any    order       column  string        any         if   value    order            order    return value       no array     if   column    column           return sortBy value        sort 1d array     if  value length  lt   1    return value       array with only one item     return orderBy value   column    order

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Angular doesn t come with an orderBy filter out of the box  but if we decide we need one we can easily make one  There are however some caveats we need to be aware of to do with speed and minification  See below   A simple pipe would look something like this   import   Pipe  PipeTransform   from   angular core     Pipe     name   sort     export class SortPipe implements PipeTransform     transform ary  any  fn  Function    a b    gt  a  gt  b   1   -1   any       return ary sort fn          This pipe accepts a sort function  fn   and gives it a default value that will sort an array of primitives in a sensible way  We have the option of overriding this sort function if we wish   It does not accept an attribute name as a string  because attribute names are subject to minification  They will change when we minify our code  but minifiers are not smart enough to also minify the value in the template string   Sorting primitives  numbers and strings   We could use this to sort an array of numbers or strings using the default comparator   import   Component   from   angular core     Component     selector   cat     template          numbers   sort         strings   sort          export class CatComponent   numbers Array lt number gt     1 7 5 6    stringsArray lt string gt      cats    hats    caveats       Sorting an array of objects  If we want to sort an array of objects  we can give it a comparator function   import   Component   from   angular core     Component     selector   cat     template          cats   sort byName          export class CatComponent   cats Array lt Cat gt           name   Missy         name   Squoodles         name   Madame Pompadomme         byName a b        return a name  gt  b name   1   -1         Caveats - pure vs  impure pipes  Angular 2 has a concept of pure and impure pipes    A pure pipe optimises change detection using object identity  This means that the pipe will only run if the input object changes identity  for example if we add a new item to the array  It will not descent into objects  This means that if we change a nested attribute  this cats 2  name    Fluffy  for example  the pipe will not rerun  This helps Angular to be fast  Angular pipes are pure by default   An impure pipe on the other hand will check object attributes  This potentially makes it much slower  Because it can t guarantee what the pipe function will do  perhaps it sortd differently based on the time of day for example   an impure pipe will run every time an asynchronous event occurs  This will slow down your app considerably if the array is large   The pipe above is pure  This means it will only run when the objects in the array are immutable  If you change a cat  you must replace the entire cat object with a new one   this cats 2     name  Tomy     We can change the above to an impure pipe by setting the pure attribute   import   Pipe  PipeTransform   from   angular core     Pipe     name   sort     pure  false    export class SortPipe implements PipeTransform     transform ary  any  fn  Function    a b    gt  a  gt  b   1   -1   any       return ary sort fn          This pipe will descend into objects  but will be slower  Use with caution

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You can use this for objects    Pipe     name   sort      export class SortPipe implements PipeTransform      transform array  any    field  string   any         return array sort  a  b    gt  a field  toLowerCase       b field  toLowerCase     a field  toLowerCase    lt  b field  toLowerCase     -1   1   0

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For Angular 5  Version we can use ngx-order-pipe package   Source Tutorial Link  Install package    npm install ngx-order-pipe --save   Import in apps module  import   BrowserModule   from   angular platform-browser   import   NgModule   from   angular core    import   FormsModule   from   angular forms   import   AppComponent   from    app component   import   OrderModule   from  ngx-order-pipe     NgModule     declarations        AppComponent        imports        BrowserModule      FormsModule      OrderModule        providers        bootstrap   AppComponent     export class AppModule       use anywhere     lt ul gt       lt li  ngFor  let item of  dummyData   orderBy  name     gt          item name        lt  li gt     lt  ul gt

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I ve created an OrderBy pipe that does just what you need  It supports being able to sort on multiple columns of an enumerable of objects as well    lt li  ngFor   todo in todos   orderBy     completed    gt   todo name     todo completed   lt  li gt    This pipe does allow for adding more items to the array after rendering the page  and will sort the array with the updates dynamically   I have a write up on the process here   And here s a working demo  http   fuelinteractive github io fuel-ui   pipe orderby and https   plnkr co edit DHLVc0 p info

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This will work for any field you pass to it   IMPORTANT  It will only order alphabetically so if you pass a date it will order it as alphabet not as date              Example use         Basic Array of single type   ngFor  let todo of todoService todos   orderBy    -           Multidimensional Array Sort on single column   ngFor  let todo of todoService todos   orderBy     -status            Multidimensional Array Sort on multiple columns   ngFor  let todo of todoService todos   orderBy     status    -title         import  Pipe  PipeTransform  from   angular core     Pipe  name   orderBy   pure  false   export class OrderByPipe implements PipeTransform        value  string              static  orderByComparator a  any  b  any   number            if  a     null    typeof a      undefined     a   0            if  b     null    typeof b      undefined     b   0             if                isNaN parseFloat a                   isFinite a                   isNaN parseFloat b       isFinite b                              Isn t a number so lowercase the string to properly compare             a   a toString                b   b toString                if  a toLowerCase    lt  b toLowerCase      return -1                if  a toLowerCase    gt  b toLowerCase      return 1              else                  Parse strings as numbers to compare properly             if  parseFloat a   lt  parseFloat b     return -1                if  parseFloat a   gt  parseFloat b     return 1                       return 0     equal each other            public transform input  any  config         any           if   input    return input                make a copy of the input s reference         this value       input           let value   this value          if   Array isArray value     return value             if   Array isArray config      Array isArray config   amp  amp  config length     1                 let propertyToCheck  string    Array isArray config    config   config 0               let desc   propertyToCheck substr 0  1       -                   Basic array             if   propertyToCheck    propertyToCheck      -     propertyToCheck                            return  desc   value sort     value sort   reverse                  else                   let property  string   propertyToCheck substr 0  1             propertyToCheck substr 0  1       -                        propertyToCheck substr 1                        propertyToCheck                   return value sort function a  any  b  any                        let aValue   a property                       let bValue   b property                        let propertySplit   property split                            if  typeof aValue      undefined   amp  amp  typeof bValue      undefined   amp  amp  propertySplit length  gt  1                            aValue   a                          bValue   b                          for  let j   0  j  lt  propertySplit length  j                                  aValue   aValue propertySplit j                                bValue   bValue propertySplit j                                                                         return  desc                           OrderByPipe  orderByComparator aValue  bValue                            -OrderByPipe  orderByComparator aValue  bValue                                               else                  Loop over property of the array in order and sort             return value sort function a  any  b  any                    for  let i   0  i  lt  config length  i                          let desc   config i  substr 0  1       -                       let property   config i  substr 0  1             config i  substr 0  1       -                            config i  substr 1                            config i                        let aValue   a property                       let bValue   b property                        let propertySplit   property split                            if  typeof aValue      undefined   amp  amp  typeof bValue      undefined   amp  amp  propertySplit length  gt  1                            aValue   a                          bValue   b                          for  let j   0  j  lt  propertySplit length  j                                  aValue   aValue propertySplit j                                bValue   bValue propertySplit j                                                                         let comparison    desc                           OrderByPipe  orderByComparator aValue  bValue                            -OrderByPipe  orderByComparator aValue  bValue                           Don t return 0 yet in case of needing to sort by next property                     if  comparison     0    return comparison                                       return 0     equal each other

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As we know filter and order by are removed from ANGULAR 2 and we need to write our own  here is a good example on plunker and detailed article  It used both filter as well as orderby  here is the code for order pipe  import   Pipe  PipeTransform   from   angular core        Pipe    name   orderBy     export class OrderrByPipe implements PipeTransform      transform records  Array lt any gt   args   any   any              return records sort function a  b             if a args property   lt  b args property                return -1   args direction                        else if  a args property   gt  b args property                return 1   args direction                        else              return 0

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This is good replacement for AngularJs orderby pipe in angular 4  Easy and simple to use   This is github URL for more information  https   github com VadimDez ngx-order-pipe  import   Pipe  PipeTransform   from   angular core     Pipe     name   orderBy     export class OrderPipe implements PipeTransform      transform value  any   any    expression   any  reverse   boolean   any       if   value          return value             const isArray   value instanceof Array       if  isArray          return this sortArray value  expression  reverse              if  typeof value      object           return this transformObject value  expression  reverse              return value                  Sort array            param value       param expression       param reverse       returns  any            private sortArray value  any    expression   any  reverse   boolean   any         const isDeepLink   expression  amp  amp  expression indexOf          -1       if  isDeepLink          expression   OrderPipe parseExpression expression              let array  any     value sort  a  any  b  any   number   gt          if   expression            return a  gt  b   1   -1                 if   isDeepLink            return a expression   gt  b expression    1   -1                 return OrderPipe getValue a  expression   gt  OrderPipe getValue b  expression    1   -1               if  reverse          return array reverse               return array                   Transform Object            param value       param expression       param reverse       returns  any            private transformObject value  any   any    expression   any  reverse   boolean   any       let parsedExpression   OrderPipe parseExpression expression       let lastPredicate   parsedExpression pop        let oldValue   OrderPipe getValue value  parsedExpression        if    oldValue instanceof Array           parsedExpression push lastPredicate         lastPredicate   null        oldValue   OrderPipe getValue value  parsedExpression              if   oldValue          return value             const newValue   this transform oldValue  lastPredicate  reverse       OrderPipe setValue value  newValue  parsedExpression       return value                  Parse expression  split into items       param expression       returns  string            private static parseExpression expression  string   string         expression   expression replace      w     g     1        expression   expression replace                 return expression split                       Get value by expression            param object       param expression       returns  any          private static getValue object  any  expression  string          for  let i   0  n   expression length  i  lt  n    i          const k   expression i         if    k in object             return                object   object k              return object                  Set value by expression            param object       param value       param expression         private static setValue object  any  value  any  expression  string          let i      for  i   0  i  lt  expression length - 1  i            object   object expression i               object expression i     value

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Updated OrderByPipe  fixed not sorting strings   create a OrderByPipe class   import   Pipe  PipeTransform   from   angular core    Pipe    name   orderBy      export class OrderByPipe implements PipeTransform   transform  array  Array lt any gt   orderField  string  orderType  boolean    Array lt string gt        array sort    a  any  b  any     gt            let ae   a  orderField            let be   b  orderField            if   ae    undefined  amp  amp  be    undefined   return 0          if   ae    undefined  amp  amp  be    undefined   return orderType   1   -1          if   ae    undefined  amp  amp  be    undefined   return orderType   -1   1          if   ae    be   return 0          return orderType    ae toString   toLowerCase    gt  be toString   toLowerCase     -1   1     be toString   toLowerCase    gt  ae toString   toLowerCase     -1   1                return array          in your controller     Component   pipes   OrderByPipe       or in your   declarations   OrderByPipe    in your html    lt tr  ngFor  let obj of objects   orderBy   ObjFieldName  OrderByType  gt       ObjFieldName  object field name you want to sort       OrderByType  boolean  true  descending order  false  ascending

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orderby Pipe in Angular JS will support but Angular  higher versions  will not support   Please find he details discussed to increase performance speed its obsolete     https   angular io guide pipes appendix-no-filterpipe-or-orderbypipe

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You could implement a custom pipe for this that leverages the sort method of arrays   import   Pipe   from  angular2 core     Pipe     name   sort     export class ArraySortPipe     transform array  Array lt string gt   args  string   Array lt string gt        array sort  a  any  b  any    gt          if  a  lt  b            return -1          else if  a  gt  b            return 1          else           return 0                      return array          And use then this pipe as described below  Don t forget to specify your pipe into the pipes attribute of the component    Component             template         lt li  ngFor  list   sort  gt         lt  li gt         pipes    ArraySortPipe              It s a simple sample for arrays with string values but you can have some advanced sorting processing  based on object attributes in the case of object array  based on sorting parameters         Here is a plunkr for this  https   plnkr co edit WbzqDDOqN1oAhvqMkQRQ p preview   Hope it helps you  Thierry

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In package json  add something like  This version is ok for Angular 2       ngx-order-pipe     1 1 3     In your typescript module  and imports array      import   OrderModule   from  ngx-order-pipe

[angular] OrderBy pipe issue

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