svelte/src/internal/client/dom/legacy/misc.js

Cybernetically enhanced web apps

import { set, source } from '../../reactivity/sources.js';
import { get } from '../../runtime.js';
import { is_array } from '../../../shared/utils.js';

/**
 * Under some circumstances, imports may be reactive in legacy mode. In that case,
 * they should be using `reactive_import` as part of the transformation
 * @param {() => any} fn
 */
export function reactive_import(fn) {
	var s = source(0);

	return function () {
		if (arguments.length === 1) {
			set(s, get(s) + 1);
			return arguments[0];
		} else {
			get(s);
			return fn();
		}
	};
}

/**
 * @this {any}
 * @param {Record<string, unknown>} $$props
 * @param {Event} event
 * @returns {void}
 */
export function bubble_event($$props, event) {
	var events = /** @type {Record<string, Function[] | Function>} */ ($$props.$$events)?.[
		event.type
	];

	var callbacks = is_array(events) ? events.slice() : events == null ? [] : [events];

	for (var fn of callbacks) {
		// Preserve "this" context
		fn.call(this, event);
	}
}

/**
 * Used to simulate `$on` on a component instance when `compatibility.componentApi === 4`
 * @param {Record<string, any>} $$props
 * @param {string} event_name
 * @param {Function} event_callback
 */
export function add_legacy_event_listener($$props, event_name, event_callback) {
	$$props.$$events ||= {};
	$$props.$$events[event_name] ||= [];
	$$props.$$events[event_name].push(event_callback);
}

/**
 * Used to simulate `$set` on a component instance when `compatibility.componentApi === 4`.
 * Needs component accessors so that it can call the setter of the prop. Therefore doesn't
 * work for updating props in `$$props` or `$$restProps`.
 * @this {Record<string, any>}
 * @param {Record<string, any>} $$new_props
 */
export function update_legacy_props($$new_props) {
	for (var key in $$new_props) {
		if (key in this) {
			this[key] = $$new_props[key];
		}
	}
}