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🔤 scopes

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This commit is contained in:
Jan Andrle 2025-03-06 09:41:29 +01:00
parent 17e40fdd9c
commit 59efa84494
4 changed files with 10 additions and 60 deletions
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2
docs/components/examples/scopes/mixed.js
View File

@ -21,9 +21,7 @@ function Counter() {
setTimeout(()=> {
// ok, BUT consider extract to separate function
// see section below for more info
scope.push();
const ok= S(0);
scope.pop();
S.on(ok, console.log);
setInterval(()=> ok.set(ok.get() + 1), 100);
}, 100);

60
docs/p05-scopes.html.js
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@ -30,7 +30,7 @@ export function page({ pkg, info }){
const page_id= info.id;
return el(simplePage, { info, pkg }).append(
el("p").append(...T`
For state-less components we can use functions as UI components (see “Elements” page). But in real life,
For state-less components we can use functions as UI components (see "Elements" page). But in real life,
we may need to handle the component live-cycle and provide JavaScript the way to properly use
the ${el("a", { textContent: t`Garbage collection`, ...references.garbage_collection })}.
`),
@ -40,9 +40,13 @@ export function page({ pkg, info }){
el(h3, t`Understanding Host Elements and Scopes`),
el("p").append(...T`
The ${el("strong", "host")} is the name for the element representing the component. This is typically
element returned by function. To get reference, you can use ${el("code", "scope.host()")} to applly addons
element returned by function. To get reference, you can use ${el("code", "scope.host()")} to apply addons
just use ${el("code", "scope.host(...<addons>)")}.
`),
el("p").append(...T`
Scopes are primarily needed when signals are used in DOM templates (with ${el("code", "el")}, ${el("code", "assign")}, or ${el("code", "S.el")}).
They provide a way for automatically removing signal listeners and cleaning up unused signals when components are removed from the DOM.
`),
el("div", { className: "illustration" }).append(
el("h4", t`Component Anatomy`),
el("pre").append(el("code", `
@ -143,63 +147,19 @@ function MyComponent() {
el("div", { className: "tab", "data-tab": "declarative" }).append(
el("h4", t`✅ Declarative Approach`),
el("p", t`Define what your UI should look like based on state:`),
el(code, { src: fileURL("./components/examples/scopes/declarative.js"), page_id }),
el(code, { src: fileURL("./components/examples/scopes/declarative.js"), page_id })
),
el("div", { className: "tab", "data-tab": "imperative" }).append(
el("h4", t`⚠️ Imperative Approach`),
el("p", t`Manually update the DOM in response to events:`),
el(code, { src: fileURL("./components/examples/scopes/imperative.js"), page_id }),
el(code, { src: fileURL("./components/examples/scopes/imperative.js"), page_id })
),
el("div", { className: "tab", "data-tab": "mixed" }).append(
el("h4", t`❌ Mixed Approach`),
el("p", t`Just AVOID:`),
el(code, { src: fileURL("./components/examples/scopes/mixed.js"), page_id }),
),
),
el(h3, t`Advanced: Custom Scoping Control`),
el("p").append(...T`
In more complex applications, you may need finer control over scopes. DDE provides
manual scope control mechanisms through ${el("code", "scope.push()")} and ${el("code", "scope.pop()")}.
`),
el("div", { className: "function-table" }).append(
el("h4", t`Manual Scope Control API`),
el("dl").append(
el("dt", t`scope.current`),
el("dd", t`Returns the currently active scope object.`),
el("dt", t`scope.isolate(callback)`),
el("dd", t`Executes the callback function within a temporary scope, then automatically restores the previous scope.
Safer than manual push/pop for most use cases.`),
el("dt", t`scope.push()`),
el("dd", t`Creates a new scope and makes it the current active scope. All signals and subscriptions
created after this call will be associated with this new scope.`),
el("dt", t`scope.pop()`),
el("dd", t`Restores the previous scope that was active before the matching push() call.`),
el(code, { src: fileURL("./components/examples/scopes/mixed.js"), page_id })
)
),
el("p").append(...T`
Custom scoping is particularly useful for:
`),
el("ul").append(
el("li", t`Isolating signal dependencies in async operations`),
el("li", t`Creating detached reactive logic that shouldn't be tied to a component's lifecycle`),
el("li", t`Building utilities that work with signals but need scope isolation`)
),
el(example, { src: fileURL("./components/examples/scopes/custom-scope.js"), page_id }),
el(example, { src: fileURL("./components/examples/scopes/with-scope.js"), page_id }),
el("div", { className: "warning" }).append(
el("p").append(...T`
${el("strong", "Be careful with manual scope control!")} Always ensure you have matching push() and pop() calls,
preferably in the same function. Unbalanced scope management can lead to memory leaks or unexpected behavior.
`),
el("p").append(...T`
For most use cases, prefer using the automatic scope management provided by components.
Manual scope control should be considered an advanced feature.
`)
),
el(h3, t`Best Practices for Scopes and Components`),
el("ol").append(
@ -236,4 +196,4 @@ function MyComponent() {
el(mnemonic)
);
}
}

2
index.d.ts vendored
View File

@ -237,8 +237,6 @@ export const scope: {
pushRoot(): ReturnType<Array<Scope>["push"]>,
/** Removes last/current child scope. */
pop(): ReturnType<Array<Scope>["pop"]>,
/** Runs function in a new (isolated) scope */
isolate(fn: Function): void,
};
export function customElementRender<

6
src/dom.js
View File

@ -72,12 +72,6 @@ export const scope= {
if(scopes.length===1) return;
return scopes.pop();
},
isolate(fn){
this.push({ prevent: true });
fn();
this.pop();
}
};
/**
* Chainable append function for elements