svelte/src/compiler/phases/3-transform/server/visitors/UpdateExpression.js

Cybernetically enhanced web apps

/** @import { UpdateExpression } from 'estree' */
/** @import { Context } from '../types.js' */
import * as b from '#compiler/builders';

/**
 * @param {UpdateExpression} node
 * @param {Context} context
 */
export function UpdateExpression(node, context) {
	const argument = node.argument;

	if (argument.type === 'Identifier') {
		const binding = context.state.scope.get(argument.name);

		if (binding?.kind === 'store_sub') {
			return b.call(
				node.prefix ? '$.update_store_pre' : '$.update_store',
				b.assignment('??=', b.id('$$store_subs'), b.object([])),
				b.literal(argument.name),
				b.id(argument.name.slice(1)),
				node.operator === '--' && b.literal(-1)
			);
		}

		if (binding?.kind === 'derived') {
			return b.call(
				node.prefix ? '$.update_derived_pre' : '$.update_derived',
				binding.node,
				node.operator === '--' && b.literal(-1)
			);
		}
	}

	return context.next();
}