Hi,
I am having a question about Boolean property value. As the doc says Boolean properties are set based on the presence of the attribute: if the attribute exists at all, the property is set to true
, regardless of the attribute value. If the attribute is absent, the property gets its default value.
Here is my experiment. my-element want to use a collapseOpened property to bind to it's local DOM iron-collapse's property 'opened'.
<iron-collapse opened="{{collapseOpened}}">
some texts
</iron-collapse>
<script>
Polymer({
is: 'my-element',
properties: {
collapseOpened: {
type: Boolean,
value: false,
}
},
});
</script>
Since in the 'opened' attribute is present in iron-collapse, should it be true? But in fact, the iron-collapse is not expanded, which indicates the value is false.
Any ideas?