What is the cmp.addValueProvider() feature designed for?











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To implement something like a public ValueProvider I implemented a component combining the features out there to have static values available in js and markup. Now I'm having trouble using the addValueProvider Feature (used for the markup side) since there is no documentation out there.



To make static values accessible for any component, I need to reference the value providing component in the concrete component like:



<!-- Value Providers -->
<c:THINGS context="{!this}" />


THINGS.cmp looks like:



<aura:component >
<aura:attribute name="context" type="Map" required="true"/>

<aura:handler name="init" value="{!this}" action="{!c.doInit}" />
</aura:component>


THINGSController.js



({
doInit: function(cmp, evt, hlp) {
const things = { FOO: "Foo", BAR: "Bar"};

cmp.get("v.context").addValueProvider("THINGS", {get: ()=>things});
}
})




Now I should be able to reference FOO like this:



<!-- Value Providers -->
<c:THINGS context="{!this}" />

<!-- Markup -->
<p>{!THINGS.FOO}</p>


The problem I encountered here is, that THINGS.FOO returns the whole Map, what renders to [object Object].



When I discovered this, I started playing around and figured out, that THINGS behaves really weird.



An init handler on my concrete component looks like this:



<aura:handler name="init" value="{!this}" action="{!c.doInit}" />


ctrl (JSON.parse&stringify to get around the proxy issue):



doInit: function(cmp, evt, hlp) {
JSON.parse(JSON.stringify( cmp.get("THINGS.value") ));
JSON.parse(JSON.stringify( cmp.get("THINGS.FOO") ));
JSON.parse(JSON.stringify( cmp.get("THINGS.x") ));
JSON.parse(JSON.stringify( cmp.get("THINGS.value.FOO") ));
JSON.parse(JSON.stringify( cmp.get("THINGS.asdasd.asdasd.asdd.ads") ));
}


The weird thing here is, that they all returned {FOO: "Foo", BAR: "Bar"}



cmp.get("THINGS") leads to an error message, not knowing what THINGS means.



Conclusion:



Value providers do only work on single values, (or maybe even lists, when we decide to iterate the result.)



cmp.addValueProvider("FOO", {get: ()=>"Foo"});


I hope you agree that this isn't a value provider, it's just a complex way to store a single value.



Quesion:



How are we supposed to use the setValueProvider feature? all I found was this answer that doesn't seem to be fully accurate.



Is there a chance to store simple key value pairs in these providers? if not, why? And where except the Aura Documentation is it documented? All it states is




Adds Custom ValueProviders to a component



Parameters key : String string by which to identify the
valueProvider. Used in expressions in markup, etc.



valueProvider : Object the object to request data from. Must
implement .get(expression), can implement .set(key,value).











share|improve this question




























    up vote
    7
    down vote

    favorite
    1












    To implement something like a public ValueProvider I implemented a component combining the features out there to have static values available in js and markup. Now I'm having trouble using the addValueProvider Feature (used for the markup side) since there is no documentation out there.



    To make static values accessible for any component, I need to reference the value providing component in the concrete component like:



    <!-- Value Providers -->
    <c:THINGS context="{!this}" />


    THINGS.cmp looks like:



    <aura:component >
    <aura:attribute name="context" type="Map" required="true"/>

    <aura:handler name="init" value="{!this}" action="{!c.doInit}" />
    </aura:component>


    THINGSController.js



    ({
    doInit: function(cmp, evt, hlp) {
    const things = { FOO: "Foo", BAR: "Bar"};

    cmp.get("v.context").addValueProvider("THINGS", {get: ()=>things});
    }
    })




    Now I should be able to reference FOO like this:



    <!-- Value Providers -->
    <c:THINGS context="{!this}" />

    <!-- Markup -->
    <p>{!THINGS.FOO}</p>


    The problem I encountered here is, that THINGS.FOO returns the whole Map, what renders to [object Object].



    When I discovered this, I started playing around and figured out, that THINGS behaves really weird.



    An init handler on my concrete component looks like this:



    <aura:handler name="init" value="{!this}" action="{!c.doInit}" />


    ctrl (JSON.parse&stringify to get around the proxy issue):



    doInit: function(cmp, evt, hlp) {
    JSON.parse(JSON.stringify( cmp.get("THINGS.value") ));
    JSON.parse(JSON.stringify( cmp.get("THINGS.FOO") ));
    JSON.parse(JSON.stringify( cmp.get("THINGS.x") ));
    JSON.parse(JSON.stringify( cmp.get("THINGS.value.FOO") ));
    JSON.parse(JSON.stringify( cmp.get("THINGS.asdasd.asdasd.asdd.ads") ));
    }


    The weird thing here is, that they all returned {FOO: "Foo", BAR: "Bar"}



    cmp.get("THINGS") leads to an error message, not knowing what THINGS means.



    Conclusion:



    Value providers do only work on single values, (or maybe even lists, when we decide to iterate the result.)



    cmp.addValueProvider("FOO", {get: ()=>"Foo"});


    I hope you agree that this isn't a value provider, it's just a complex way to store a single value.



    Quesion:



    How are we supposed to use the setValueProvider feature? all I found was this answer that doesn't seem to be fully accurate.



    Is there a chance to store simple key value pairs in these providers? if not, why? And where except the Aura Documentation is it documented? All it states is




    Adds Custom ValueProviders to a component



    Parameters key : String string by which to identify the
    valueProvider. Used in expressions in markup, etc.



    valueProvider : Object the object to request data from. Must
    implement .get(expression), can implement .set(key,value).











    share|improve this question


























      up vote
      7
      down vote

      favorite
      1









      up vote
      7
      down vote

      favorite
      1






      1





      To implement something like a public ValueProvider I implemented a component combining the features out there to have static values available in js and markup. Now I'm having trouble using the addValueProvider Feature (used for the markup side) since there is no documentation out there.



      To make static values accessible for any component, I need to reference the value providing component in the concrete component like:



      <!-- Value Providers -->
      <c:THINGS context="{!this}" />


      THINGS.cmp looks like:



      <aura:component >
      <aura:attribute name="context" type="Map" required="true"/>

      <aura:handler name="init" value="{!this}" action="{!c.doInit}" />
      </aura:component>


      THINGSController.js



      ({
      doInit: function(cmp, evt, hlp) {
      const things = { FOO: "Foo", BAR: "Bar"};

      cmp.get("v.context").addValueProvider("THINGS", {get: ()=>things});
      }
      })




      Now I should be able to reference FOO like this:



      <!-- Value Providers -->
      <c:THINGS context="{!this}" />

      <!-- Markup -->
      <p>{!THINGS.FOO}</p>


      The problem I encountered here is, that THINGS.FOO returns the whole Map, what renders to [object Object].



      When I discovered this, I started playing around and figured out, that THINGS behaves really weird.



      An init handler on my concrete component looks like this:



      <aura:handler name="init" value="{!this}" action="{!c.doInit}" />


      ctrl (JSON.parse&stringify to get around the proxy issue):



      doInit: function(cmp, evt, hlp) {
      JSON.parse(JSON.stringify( cmp.get("THINGS.value") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.FOO") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.x") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.value.FOO") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.asdasd.asdasd.asdd.ads") ));
      }


      The weird thing here is, that they all returned {FOO: "Foo", BAR: "Bar"}



      cmp.get("THINGS") leads to an error message, not knowing what THINGS means.



      Conclusion:



      Value providers do only work on single values, (or maybe even lists, when we decide to iterate the result.)



      cmp.addValueProvider("FOO", {get: ()=>"Foo"});


      I hope you agree that this isn't a value provider, it's just a complex way to store a single value.



      Quesion:



      How are we supposed to use the setValueProvider feature? all I found was this answer that doesn't seem to be fully accurate.



      Is there a chance to store simple key value pairs in these providers? if not, why? And where except the Aura Documentation is it documented? All it states is




      Adds Custom ValueProviders to a component



      Parameters key : String string by which to identify the
      valueProvider. Used in expressions in markup, etc.



      valueProvider : Object the object to request data from. Must
      implement .get(expression), can implement .set(key,value).











      share|improve this question















      To implement something like a public ValueProvider I implemented a component combining the features out there to have static values available in js and markup. Now I'm having trouble using the addValueProvider Feature (used for the markup side) since there is no documentation out there.



      To make static values accessible for any component, I need to reference the value providing component in the concrete component like:



      <!-- Value Providers -->
      <c:THINGS context="{!this}" />


      THINGS.cmp looks like:



      <aura:component >
      <aura:attribute name="context" type="Map" required="true"/>

      <aura:handler name="init" value="{!this}" action="{!c.doInit}" />
      </aura:component>


      THINGSController.js



      ({
      doInit: function(cmp, evt, hlp) {
      const things = { FOO: "Foo", BAR: "Bar"};

      cmp.get("v.context").addValueProvider("THINGS", {get: ()=>things});
      }
      })




      Now I should be able to reference FOO like this:



      <!-- Value Providers -->
      <c:THINGS context="{!this}" />

      <!-- Markup -->
      <p>{!THINGS.FOO}</p>


      The problem I encountered here is, that THINGS.FOO returns the whole Map, what renders to [object Object].



      When I discovered this, I started playing around and figured out, that THINGS behaves really weird.



      An init handler on my concrete component looks like this:



      <aura:handler name="init" value="{!this}" action="{!c.doInit}" />


      ctrl (JSON.parse&stringify to get around the proxy issue):



      doInit: function(cmp, evt, hlp) {
      JSON.parse(JSON.stringify( cmp.get("THINGS.value") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.FOO") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.x") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.value.FOO") ));
      JSON.parse(JSON.stringify( cmp.get("THINGS.asdasd.asdasd.asdd.ads") ));
      }


      The weird thing here is, that they all returned {FOO: "Foo", BAR: "Bar"}



      cmp.get("THINGS") leads to an error message, not knowing what THINGS means.



      Conclusion:



      Value providers do only work on single values, (or maybe even lists, when we decide to iterate the result.)



      cmp.addValueProvider("FOO", {get: ()=>"Foo"});


      I hope you agree that this isn't a value provider, it's just a complex way to store a single value.



      Quesion:



      How are we supposed to use the setValueProvider feature? all I found was this answer that doesn't seem to be fully accurate.



      Is there a chance to store simple key value pairs in these providers? if not, why? And where except the Aura Documentation is it documented? All it states is




      Adds Custom ValueProviders to a component



      Parameters key : String string by which to identify the
      valueProvider. Used in expressions in markup, etc.



      valueProvider : Object the object to request data from. Must
      implement .get(expression), can implement .set(key,value).








      lightning-components documentation value-providers






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited 3 hours ago

























      asked 3 hours ago









      Basti

      3,8961949




      3,8961949






















          1 Answer
          1






          active

          oldest

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          up vote
          7
          down vote



          accepted










          The value provider's get method requires a key to retrieve the value from the map/object. So with your value providers get method returning the entire map you will always get the output of [object Object]. By changing your get method in the addValueProvider function to .addValueProvider("THINGS", {get: (k)=>things[k]});,
          when retrieving {!THINGS.FOO} you will get Foo and likewise with {!THINGS.BAR} you would get Bar





          Additionally if you also want to be able to update or add new values to the value provider you need to also include a set method.
          .addValueProvider("THINGS", {get: (k)=>things[k], set: (k, v)=>things[k]=v});






          share|improve this answer





















          • Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
            – Basti
            57 mins ago










          • No problem. Unfortunately this happens to us all
            – Jonathon Chambers
            45 mins ago











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          active

          oldest

          votes








          up vote
          7
          down vote



          accepted










          The value provider's get method requires a key to retrieve the value from the map/object. So with your value providers get method returning the entire map you will always get the output of [object Object]. By changing your get method in the addValueProvider function to .addValueProvider("THINGS", {get: (k)=>things[k]});,
          when retrieving {!THINGS.FOO} you will get Foo and likewise with {!THINGS.BAR} you would get Bar





          Additionally if you also want to be able to update or add new values to the value provider you need to also include a set method.
          .addValueProvider("THINGS", {get: (k)=>things[k], set: (k, v)=>things[k]=v});






          share|improve this answer





















          • Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
            – Basti
            57 mins ago










          • No problem. Unfortunately this happens to us all
            – Jonathon Chambers
            45 mins ago















          up vote
          7
          down vote



          accepted










          The value provider's get method requires a key to retrieve the value from the map/object. So with your value providers get method returning the entire map you will always get the output of [object Object]. By changing your get method in the addValueProvider function to .addValueProvider("THINGS", {get: (k)=>things[k]});,
          when retrieving {!THINGS.FOO} you will get Foo and likewise with {!THINGS.BAR} you would get Bar





          Additionally if you also want to be able to update or add new values to the value provider you need to also include a set method.
          .addValueProvider("THINGS", {get: (k)=>things[k], set: (k, v)=>things[k]=v});






          share|improve this answer





















          • Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
            – Basti
            57 mins ago










          • No problem. Unfortunately this happens to us all
            – Jonathon Chambers
            45 mins ago













          up vote
          7
          down vote



          accepted







          up vote
          7
          down vote



          accepted






          The value provider's get method requires a key to retrieve the value from the map/object. So with your value providers get method returning the entire map you will always get the output of [object Object]. By changing your get method in the addValueProvider function to .addValueProvider("THINGS", {get: (k)=>things[k]});,
          when retrieving {!THINGS.FOO} you will get Foo and likewise with {!THINGS.BAR} you would get Bar





          Additionally if you also want to be able to update or add new values to the value provider you need to also include a set method.
          .addValueProvider("THINGS", {get: (k)=>things[k], set: (k, v)=>things[k]=v});






          share|improve this answer












          The value provider's get method requires a key to retrieve the value from the map/object. So with your value providers get method returning the entire map you will always get the output of [object Object]. By changing your get method in the addValueProvider function to .addValueProvider("THINGS", {get: (k)=>things[k]});,
          when retrieving {!THINGS.FOO} you will get Foo and likewise with {!THINGS.BAR} you would get Bar





          Additionally if you also want to be able to update or add new values to the value provider you need to also include a set method.
          .addValueProvider("THINGS", {get: (k)=>things[k], set: (k, v)=>things[k]=v});







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 1 hour ago









          Jonathon Chambers

          1788




          1788












          • Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
            – Basti
            57 mins ago










          • No problem. Unfortunately this happens to us all
            – Jonathon Chambers
            45 mins ago


















          • Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
            – Basti
            57 mins ago










          • No problem. Unfortunately this happens to us all
            – Jonathon Chambers
            45 mins ago
















          Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
          – Basti
          57 mins ago




          Oh, wow, totally missed that get(expression) thing in the documentation. Thank you so much, I already gave up on having a proper value provider, you saved my feature :D
          – Basti
          57 mins ago












          No problem. Unfortunately this happens to us all
          – Jonathon Chambers
          45 mins ago




          No problem. Unfortunately this happens to us all
          – Jonathon Chambers
          45 mins ago


















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