CallExpression() — svelte Function Reference

Source Code

packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js lines 13–118

export function CallExpression(node, context) {
	const rune = get_rune(node, context.state.scope);

	switch (rune) {
		case '$host':
			return b.id('$$props.$$host');

		case '$effect.tracking':
			return b.call('$.effect_tracking');

		// transform state field assignments in constructors
		case '$state':
		case '$state.raw': {
			let arg = node.arguments[0];

			/** @type {Expression | undefined} */
			let value = undefined;

			if (arg) {
				value = /** @type {Expression} */ (context.visit(node.arguments[0]));

				if (
					rune === '$state' &&
					should_proxy(/** @type {Expression} */ (arg), context.state.scope)
				) {
					value = b.call('$.proxy', value);
				}
			}

			const callee = b.id('$.state', node.callee.loc);
			return b.call(callee, value);
		}

		case '$derived':
		case '$derived.by': {
			let fn = /** @type {Expression} */ (context.visit(node.arguments[0]));

			return b.call('$.derived', rune === '$derived' ? b.thunk(fn) : fn);
		}

		case '$state.eager':
			return b.call(
				'$.eager',
				b.thunk(/** @type {Expression} */ (context.visit(node.arguments[0])))
			);

		case '$state.snapshot':
			return b.call(
				'$.snapshot',
				/** @type {Expression} */ (context.visit(node.arguments[0])),
				is_ignored(node, 'state_snapshot_uncloneable') && b.true
			);

		case '$effect':
		case '$effect.pre': {
			const callee = rune === '$effect' ? '$.user_effect' : '$.user_pre_effect';
			const func = /** @type {Expression} */ (context.visit(node.arguments[0]));

			const expr = b.call(callee, /** @type {Expression} */ (func));
			expr.callee.loc = node.callee.loc; // ensure correct mapping

			return expr;
		}

		case '$effect.root':
			return b.call(
				'$.effect_root',
				.../** @type {Expression[]} */ (node.arguments.map((arg) => context.visit(arg)))
			);

		case '$effect.pending':
			return b.call('$.eager', b.thunk(b.call('$.pending')));

		case '$inspect':
		case '$inspect().with':
			return transform_inspect_rune(rune, node, context);
	}

	if (
		dev &&
		node.callee.type === 'MemberExpression' &&