ng-change get new value and original value

Question

I m using ng-options to select values from a pulldown  I d like to be able to compare the old value to the new value  ng-change works well for grabbing the new value of the pull down  but how can I get both the new value and the original value    lt select ng-change  updateValue user   ng-model  user id  ng-options  user id as user name for user in users  gt  lt  select gt     For instance  let s say I wanted the controller to log   Your former user name was BILL  your current user name is PHILLIPE

User · Answer

You can always do      ng-model  quot file PLIK STATUS quot  ng-change  quot file PLIK STATUS   setFileStatus file PLIK ID file PLIK STATUS    file PLIK STATUS     quot       and in controller   scope setFileStatus   function  plik id  new status  old status        var answer   confirm  Czy na pewno zmienic status dla pliku          if  answer            podasysService setFileStatus plik id  new status  then function  result                return new status                   else          return old status

User · Answer

With an angular   expression   you can add the old user or user id value to the ng-change attribute as a literal string    lt select ng-change  updateValue user     user id               ng-model  user id  ng-options  user id as user name for user in users  gt   lt  select gt    On ngChange  the 1st argument to updateValue will be the new user value  the 2nd argument will be the literal that was formed when the select-tag was last updated by angular  with the old user id value

User · Answer

Just keep a currentValue variable in your controller that you update on every change  You can then compare that to the new value every time before you update it    The idea of using a watch is good as well  but I think a simple variable is the simplest and most logical solution

User · Answer

You can use something like ng-change someMethod   user id     By keeping your value in side   expression   it will evaluate expression in-line and gives you current value value before ng-change method is called     lt select ng-model  selectedValue  ng-change  change selectedValue     selectedValue      gt

User · Answer

You can use a scope watch    scope  watch  user   function newValue  oldValue         access new and old value here   console log  Your former user name was   oldValue name    you re current user name is   newValue name             https   docs angularjs org api ng type  rootScope Scope  watch

User · Answer

You could use a watch instead  because that has the old and new value  but then you re adding to the digest cycle   I d just keep a second variable in the controller and set that

User · Answer

Also you can use    lt select ng-change  updateValue user  oldValue               ng-init  oldValue 0         ng-focus  oldValue user id         ng-model  user id  ng-options  user id as user name for user in users  gt   lt  select gt

[angularjs] ng-change get new value and original value

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