stringified-handler
v0.4.3
Published
A super simple approach to SSR events handling through object literals.
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stringified handler
A super simple approach to SSR events handling through object literals.
import StringifiedHandler from 'stringified-handler';
// define a handler
const handler = StringifiedHandler({
clickCounts: 0,
onClick(event) {
event.preventDefault();
console.log(++this.clickCounts);
}
});
// create some content via SSR
console.log(`
<!doctype html>
<script>${handler}</script>
<body onclick=${handler.onClick}>
<h1>Hello World</h1>
</body>
`);The handler.toString() will produce the following:
var _$H0={
clickCounts:0,
onClick:function(event) {
event.preventDefault();
console.log(++this.clickCounts);
}
};While the handler.onClick, as string, will return _$H0.onClick(event), which is suitable for any DOM Level 0 event attached directly to its layout.
If used directly, handler.onClick would be a function bound to the handler, so that it can be reused with client-side libraries too right away.
The library, used via SSR, costs zero extra bytes, as the only payload depends on how big is the handler. Using JS minifiers after .toString() might also help reducing further more the payload size.
Usage & Limitations
The object literal must be quite simple, and none of its methods, functions, utilities, can refer to any outer scope, unless whatever it's using is reachable because the dependency has been previously injected too.
In few words, no outer scope allowed, and following there's an explanation of what can be serialized:
StringifiedHandler({
// any JSON serializable value is fine, and
// objects and arrays will be recursively parsed
serializable: {} || [] || true || false || null ||
number || string || undefined,
// getters and setters are OK
get prop() {},
set prop(value) {},
// shorthand methods are OK and normalized for legacy
method(one, orMore, values) {},
// regular functions are OK too
methodFn: function (a, b, c) {},
// arrows are also OK but not normalized for legacy
methodArr: e => {},
// spread arguments and defaults are also OK
// but not normalized for legacy
// generators, as well as async function,
// are possible too
async short() {},
methodAsync: async function () {},
*generator() {}
});Such object could handle state changes, or delegate to a third parts library, as long as this is already available on the global context, before a user interacts.
How to know which node triggered the event?
Every event object contains a currentTarget property, which refers to the node that actually had the event attached, while the target could be any inner node that triggered initially such event.
A click in the H1 element, as example, would have currentTarget pointing at the BODY, and the target pointing at the H1 element.
<!doctype html>
<script>${handler}</script>
<body onclick=${handler.onClick}>
<h1>Hello World</h1>
</body>