feat(versioning): use native custom element lifecycle #3352
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -8,67 +8,58 @@ import { isUndefined } from '@lwc/shared'; | |
| import type { LifecycleCallback } from '@lwc/engine-core'; | ||
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| const cachedConstructors = new Map<string, CustomElementConstructor>(); | ||
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| let elementBeingUpgradedByLWC = false; | ||
| let upgradeCallbackToUse: LifecycleCallback | undefined; | ||
| let connectedCallbackToUse: LifecycleCallback | undefined; | ||
| let disconnectedCallbackToUse: LifecycleCallback | undefined; | ||
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| const instancesToConnectedCallbacks = new WeakMap<HTMLElement, LifecycleCallback>(); | ||
| const instancesToDisconnectedCallbacks = new WeakMap<HTMLElement, LifecycleCallback>(); | ||
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| // Creates a constructor that is intended to be used directly as a custom element, except that the upgradeCallback is | ||
| // passed in to the constructor so LWC can reuse the same custom element constructor for multiple components. | ||
| // Another benefit is that only LWC can create components that actually do anything – if you do | ||
| // `customElements.define('x-foo')`, then you don't have access to the upgradeCallback, so it's a dummy custom element. | ||
| // This class should be created once per tag name. | ||
| const createUpgradableConstructor = () => { | ||
| // TODO [#2972]: this class should expose observedAttributes as necessary | ||
| return class UpgradableConstructor extends HTMLElement { | ||
| constructor() { | ||
| super(); | ||
| // If the element is not created using lwc.createElement(), e.g. `document.createElement('x-foo')`, | ||
| // then elementBeingUpgraded will be false | ||
| if (elementBeingUpgradedByLWC) { | ||
| // Cache the callbacks in the weak maps | ||
| instancesToConnectedCallbacks.set(this, connectedCallbackToUse!); | ||
| instancesToDisconnectedCallbacks.set(this, disconnectedCallbackToUse!); | ||
| upgradeCallbackToUse!(this); | ||
| } | ||
| // TODO [#2970]: LWC elements cannot be upgraded via new Ctor() | ||
| // Do we want to support this? Throw an error? Currently for backwards compat it's a no-op. | ||
| } | ||
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There was a problem hiding this comment. What I'm doing here is a known perf regression (adding the We may be able to solve the perf regression if we do #3202 someday. |
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| connectedCallback() { | ||
| const connectedCallback = instancesToConnectedCallbacks.get(this); | ||
| if (!isUndefined(connectedCallback)) { | ||
| connectedCallback(this); | ||
| } | ||
| } | ||
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| disconnectedCallback() { | ||
| const disconnectedCallback = instancesToDisconnectedCallbacks.get(this); | ||
| if (!isUndefined(disconnectedCallback)) { | ||
| disconnectedCallback(this); | ||
| } | ||
| } | ||
| }; | ||
| }; | ||
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| export const createCustomElementUsingUpgradableConstructor = ( | ||
| tagName: string, | ||
| upgradeCallback: LifecycleCallback, | ||
| connectedCallback: LifecycleCallback, | ||
| disconnectedCallback: LifecycleCallback | ||
| ) => { | ||
| // use global custom elements registry | ||
| let UpgradableConstructor = cachedConstructors.get(tagName); | ||
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@@ -79,18 +70,21 @@ export const createCustomElementUsingUpgradableConstructor = ( | |
| `Unexpected tag name "${tagName}". This name is a registered custom element, preventing LWC to upgrade the element.` | ||
| ); | ||
| } | ||
| UpgradableConstructor = createUpgradableConstructor(); | ||
| customElements.define(tagName, UpgradableConstructor); | ||
| cachedConstructors.set(tagName, UpgradableConstructor); | ||
| } | ||
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| elementBeingUpgradedByLWC = true; | ||
| upgradeCallbackToUse = upgradeCallback; | ||
| connectedCallbackToUse = connectedCallback; | ||
| disconnectedCallbackToUse = disconnectedCallback; | ||
| try { | ||
| return new UpgradableConstructor(); | ||
| } finally { | ||
| elementBeingUpgradedByLWC = false; | ||
| upgradeCallbackToUse = undefined; | ||
| connectedCallbackToUse = undefined; | ||
| disconnectedCallbackToUse = undefined; | ||
| } | ||
| }; | ||
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I would love to use the
integertype here, but I could not get it to work, and I figured there's little point in debugging Circle CI oddities since we may move away from Circle CI anyway.