I was looking at dom-repeaters with the template tag. So i was going to walk an array. I wanted to then walk the properties of the object itself.
I didnt see anything online though. I was thinking of something like
<template is="dom-repeat" items="{{data}}" as="row">
<template is="dom-repeat" items="{{row}}" as="prop">
<div>{{prop}}</div>
</template>
</tempalate>
but the console throws one of those terrible stack traces about null not having the method "_badUpgrade". Maybe there is better documentation for 1.0 Polymer as to repeating over a dynamic object?
My end state is to create a datagrid allowing dynamic headers and dynamic data.... so the keys of the headers have to be a subset of the data properties so the correct items are assigned under the correct columns etc
Related
I read carefully these threads
Polymer 1 nested dom-if within dom-repeat not updating when data changes
how to dynamically append an element to dom-if in Polymer?
How to access content of dom-if inside a custom element?
that may have some relation with my question but I didn't manage find any clue if I can do what I want and how.
In my company, there are several flows, each one for each business flow and each step of the flow is a screen coded as a Polymer 1 web component. All them are warraped in a root Polymer component which defines the route.
A simple exemple would be:
my-root-component:
<dom-module id="my-root-component">
<template>
<first-obrigatiory-page which-route={aValueReturnedFromFirstComponent}></first-obrigatiory-page>
<template is="dom-if" if="[[_isTrueFunction(aValueReturnedFromFirstComponent)]]" restamp>
<second-page which-sub-route={aValueReturnedFromSecondComponent}></second-page>
<template is="dom-if" if="[[_isTrueFunction(aValueReturnedFromSecondComponentComponent)]]" restamp>
<third-page ></third-page>
</template>
</template>
</template>
<script>
Polymer({
is: 'my-root-component',
behaviors: [doesntMatterHere],
properties: {
The first dom-if works as expected but the second seems not be taken in account and my third-page component is never showed.
I checked and the equivalent for _isTrueFunction(aValueReturnedFromSecondComponentComponent) is returning true.
Does aValueReturnedFromFirstComponent really return anything, because you should declare the attribute as which-route="{{aValueReturnedFromFirstComponent}}" instead of using simple { }.
Does the whichRoute (note the camelCase) property in the first-obrigatiory-page element have the notify: true property so the variable actually sends back the updated value?
I usually set observers on variables whenever dom-ifs don't update so I can see if they really change or not, and then set the variables myself through the console with document.querySelector('my-root-component').set('aValueReturnedFromFirstComponent', true) so I can see that the dom-if really updates.
A workaround could be to use events, but what you've done should work.
I have a template dom-repeat element. I know that I can define the items attribute from an array, so that item can be accessed inside the template. However, I don't know how to access other objects inside the template if I bind them to customer polymer elements.
In this example, items is being defined by someItems, and item is passed into the element <my-el>. I also have a string mine that I want to pass into <my-el> and use there. I currently have the idea to do this in app-el.html, which contains the dom-repeat template:
app-el.html
<template is="dom-repeat" items="[[someItems]]">
<my-el item=[[item]] mine="[[mine]]"></my-el><br>
</template>
In theory, I would be able to access both in my-el.html like this:
my-el.html
[[item]] [[mine]]
However, when I try to access mine from inside <my-el> it is undefined. How can I correctly pass in this string so I can access it?
An MCVE can be found on this Plunker. Note how the item string is defined inside <my-el> but the mine string is not.
Your data bindings look correct, but there is no mine property for my-app. Did you mean to define <my-app>.myProperty as <my-app>.mine? Changing that property name to mine fixes your problem.
plunker
How do you make dom-if templates within dom-repeat's update when the data changes??
Example here http://jsbin.com/xatala/edit?html,output
In the example the data changes after 1.5 seconds but the dom-if's inside the template aren't re-evaluated/rendered. You can see this in the console.log. The data has changed but the view isn't updated.
How would you make this work and what is the reasoning behind it?!
Here is example that works: http://jsbin.com/nejadibuju/edit?html,console,output
<template is="dom-if"
if="{{arrayItem(myItems.*, index, 'isGood')}}">
[[item.title]] is SOOO good.
</template>
What you were missing is:
Explicit bindings to array items by index isn’t supported
Some explanations are added in the Bin.
Related links:
Polymer, binding to array items not working
http://plnkr.co/edit/aOmw4e?p=preview
We're developing a data visualization library using Polymer, and I must say I'm impressed with what Polymer lets you do. We do have a question, though...
First: here's an example snippet of code showing a data visualization:
<template is="auto-binding">
<our-loaddata url="data/data.csv" data="{{data}}"></our-loaddata>
<our-scatterplot data="{{data}}"></our-scatterplot>
<our-barchart data="{{data}}" dimension="weight"></our-barchart>
<our-histogram data="{{data}}" dimension="weight" binSize=10></our-histogram>
</template>
The our-loaddata loads the dataset from a file data/data.csv, performs some transformations (e.g. converting strings to numbers, calculating distributions, ...) and makes it available through {{data}} to the our-scatterplot, our-barchart and our-histogram. However, I'm not completely satisfied with the setup. Conceptually, the our-loaddata is different from the other three, and should precede them. As an alternative, we have also tried the following (renaming loaddata to app and nesting all visuals within the app):
<template is="auto-binding">
<our-app url="data/data.csv" data="{{data}}">
<our-scatterplot data="{{data}}"></our-scatterplot>
<our-barchart data="{{data}}" dimension="weight"></our-barchart>
<our-histogram data="{{data}}" dimension="weight" binSize=10></our-histogram>
</our-app>
</template>
Although this also works, we noticed that it doesn't matter if we close the </our-app> element before or after all the visual elements.
What would be the most canonical way to handle this in Polymer? What is the difference between the approaches that I showed here?
you could use the conditional template to check if data is present and then send the other elements to the dom if true or show a loader if false. (careful getting to used to this i don't think it is currently in 0.8. sad IMO i <3 it)
<template is="auto-binding">
<our-loaddata url="data/data.csv" data="{{data}}"></our-loaddata>
<template if="{{data}}">
<our-scatterplot data="{{data}}"></our-scatterplot>
<our-barchart data="{{data}}" dimension="weight"></our-barchart>
<our-histogram data="{{data}}" dimension="weight" binSize=10></our-histogram>
</template>
<template if="{{!data}}">
<pretty-loadingscreen></pretty-loadingscreen>
</template>
</template>
the would give you seperation of elements you were looking for.
I would like to bind attr and attr1 in the following example. These two parameters do not depend on data (other attributes do). When using the binding this way, there is only one shared data object between all 'rows'. I want only the two components of one iteration to be bound together.
<template repeat"{{data in dataList}}">
<component1 attr="{{binding}}" />
<component2 attr2="{{binding}}" />
</template>
My first idea was to bind the attributes to an variable of the data object:
<template repeat"{{data in dataList}}">
<component1 attr="{{data.binding}}" />
<component2 attr2="{{data.binding}}" />
</template>
This solution on the other hand is really ugly, because the model object get's view-only data attached. Because the model lives normally longer than the components, this could cause a huge overhead. Another problem is serialization, which could fail because of the attached data.
Is there any elegant solution? The only one I imagined so far is to wrap the data objects before iterating over the data set. This approach on the other hand would probably make problems with model updates...
Naive thought: Shouldn't be the scope of a variable that is only used inside of a template restricted to this template? In the special case of the repeat template furthermore to one iteration?
You might type-suggest your binding variable being an Object and use it like:
<polymer-element name="my-element" attributes="dataList">
<template>
<ul>
<template repeat="{{d in dataList}}">
<li>
{{d}} ⇒ {{binding[d]}} <!-- Since type-suggested, it works -->
</li>
</template>
</ul>
</template>
<script>
Polymer({
dataList: ['navy', 'maroon'],
binding: {} /* it’s necessary to type-suggest var for Polymer */
});
</script>
</polymer-element>
Please be aware that the snippet above expects different items in dataList. Live preview: http://plnkr.co/edit/ez36BVUPCKW8xRSkGxOM?p=preview
Naive thought: Shouldn't be the scope of a variable that is only used inside of a template restricted to this template? In the special case of the repeat template furthermore to one iteration?
This sounds impossible for me, because (besides that this will overcomplicate the implementation) sometimes one wants to bind the variable in nested template:
<template repeat="{{a in lst}}">
{{bound_here}}
<template id="nested">
{{bound_here}}
...
With what you suggested the binding above becomes impossible.