Using Pipes within ngModel on INPUT Elements in Angular

Question

I ve an HTML INPUT field    lt input        ngModel    item value       name  inputField       type  text     gt    and I want to format its value and use an existing pipe           ngModel    item value   useMyPipeToFormatThatValue          and get the error message      Cannot have a pipe in an action expression   How can I use pipes in this context

User · Accepted Answer

You can t use Template expression operators pipe  save navigator  within template statement      ngModelChange   Template statements     ngModelChange   item value   useMyPipeToFormatThatValue  event   https   angular io guide template-syntax template-statements     Like template expressions  template statements use a language that   looks like JavaScript  The template statement parser differs from the   template expression parser and specifically supports both basic   assignment     and chaining expressions  with   or          However  certain JavaScript syntax is not allowed          new   increment and decrement operators     and --   operator assignment  such as    and -    the bitwise operators   and  amp    the template expression operators      So you should write it as follows    lt input  ngModel   item value   useMyPipeToFormatThatValue          ngModelChange   item value  event  name  inputField  type  text    gt    Plunker  Example

User · Answer

I tried the solutions above yet the value that goes to the model were the formatted value then returning and giving me currencyPipe errors  So i had to     ngModel   transfer amount   currency  USD  true                                      blur   addToAmount  event target value                                       keypress   validateOnlyNumbers  event     And on the function of addToAmount -  change on blur cause the ngModelChange was giving me cursor issues   removeCurrencyPipeFormat formatedNumber       return formatedNumber replace       g           And removing the other non numeric values   validateOnlyNumbers evt      var theEvent   evt    window event    var key   theEvent keyCode    theEvent which    key   String fromCharCode  key      var regex     0-9         if   regex test key          theEvent returnValue   false      if theEvent preventDefault  theEvent preventDefault

User · Answer

My Solution is given below here searchDetail is an object     lt p-calendar   ngModel   searchDetail queryDate   date  MM dd yyyy     ngModelChange   searchDetail queryDate  event   showIcon   true  required name  queryDate  placeholder  Enter the Query Date  gt  lt  p-calendar gt    lt input id  float-input  type  text  size  30  pInputText  ngModel   searchDetail systems   json    ngModelChange   searchDetail systems  event  required  true  name  systems              placeholder  Enter the Systems  gt

User · Answer

lt input  ngModel   item value   currency   ngModelChange   item value  event  name  name  type  text    gt    I would like to add one more point to the accepted answer   If the type of your input control is not text the pipe will not work   Keep it in mind and save your time

User · Answer

you must use  ngModel  instead of two way model binding with   ngModel    then use manual change event with  ngModelChange   this is public rule for all two way input in components   because pipe on event emitter is wrong

User · Answer

because of two way binding  To prevent error of   ExpressionChangedAfterItHasBeenCheckedError  Expression has changed after it was  checked    you can call a function to change model like this    lt input  ngModel   item value      ngModelChange   getNewValue  event   name  inputField  type  text    gt    import   UseMyPipeToFormatThatValuePipe   from    path    constructor       private UseMyPipeToFormatThatValue  UseMyPipeToFormatThatValuePipe      getNewValue ev  any   any       item value  this useMyPipeToFormatThatValue transform ev       it ll be good if there is a better solution to prevent this error

User · Answer

lt input  ngModel   item value   useMyPipeToFormatThatValue          ngModelChange   item value  event  name  inputField  type  text    gt    The solution here is to split the binding into a one-way binding and an event binding - which the syntax   ngModel   actually encompasses     is one-way binding syntax and    is event binding syntax  When used together -      Angular recognizes this as shorthand and wires up a two-way binding in the form of a one-way binding and an event binding to a component object value   The reason you cannot use      with a pipe is that pipes work only with one-way bindings  Therefore you must split out the pipe to only operate on the one-way binding and handle the event separately   See Angular Template Syntax for more info

[angular] Using Pipes within ngModel on INPUT Elements in Angular

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