Add docs for defaultValue #1396
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justinfagnani
approved these changes
Feb 4, 2025
| import {customElement, property} from 'lit/decorators.js'; | ||
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| @customElement('my-element') | ||
| class MyElement extends LitElement { | ||
| @property({type: Boolean, reflect: true}) | ||
| active: boolean = false; | ||
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| @property({type: String, reflect: true, defaultValue: 'normal'} as PropertyDeclaration) |
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Is this cast only needed until lit/lit#4895 is released?
| @@ -129,10 +129,13 @@ class MyElement extends LitElement { | |||
| } | |||
| ``` | |||
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| In **JavaScript**, you **must not use class fields** when declaring reactive properties. Instead, properties must be initialized in the element constructor: | |||
| In **JavaScript**, you **must not use class fields** when declaring reactive properties. Instead, properties must be either initialized in the element constructor or set with the `defaultValue` option: | |||
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While you're here "Instead" reads a little unclearly to me. I think saying "to initialize properties" would help somewhere. Also, "JavaScript" now has decorators via Babel at least, so maybe we update that phrase too.
Maybe:
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| In **JavaScript**, you **must not use class fields** when declaring reactive properties. Instead, properties must be either initialized in the element constructor or set with the `defaultValue` option: | |
| If you are declaring reactive properties with the static properties class field, and not using decorators, you **must not use class fields** for those properties. Class fields will overwrite the properties in the static properties class field, disabling reactivity. To initialize a reactive property, do so in the element constructor or set the `defaultValue` option: |
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Adds docs for lit/lit#4895. Publish on after that release.