geoloeg / dom-repeat-n

[Polymer 1.x] A template element that repeat n times its content.

<dom-repeat-n>

Descripton

A template element that repeat n times its content.

Install

Install the component using Bower:

$ bower install dom-repeat-n --save

Usage

Import Custom Element:

<link rel="import" href="bower_components/dom-repeat-n/dom-repeat-n.html">

And then use it:

<template is="dom-repeat-n" count="3">
  <div>I am div {{index}}</div>
</template>

See the Documentation for more options.

More Demos

https://geoloeg.github.io/dom-repeat-n/

Discussing

If you have any questions, you can find me on the Polymer Slack Channel, or just raise an Issue.

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -m 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

dom-repeat-n's Issues

TypeError when reducing the count to less than half

The 'dom-repeat-n' template causes a TypeError when reducing the count by a large amount (e.g. from 4 to 1).

polymer-mini.html:2046 Uncaught TypeError: Cannot read property '_children' of undefined(…)_detachInstance @ dom-repeat-n.html:172

The problem is that method '_countChanged' iterates over the 'instances' array while at the same time removing values from it. This fails when removing more than half of the entries as the length of the array is then lower than the used index.

I managed to locally fix this problem by reversing the order, in which the iteration is performed. I replace the following line:

for (i=newCount; i<limit; i++) {

with

for (i=limit-1; i>newCount-1; i--) {

Polymer 2 Support

Hello! 👋

I find dom-repeat-n very useful, and I have implemented it in several of my projects. I'm now porting those projects to Polymer 2, and would like to continue using dom-repeat-n. I see that work has begun on upgrading this element to Polymer 2, but it seems that more work still needs to be done. Is there a list of
remaining tasks I could help out with?

`inst` is undefined in _render loop

Seems that _render is sometimes being called with _instances not being of the same length as this.count, which causes the inst variable inside the loop to be undefined.

Either patching render to loop over _instances instead, or patching being called while _instances is out of parity with count should do the trick.

Add an increment property