All files / src/compiler/phases/3-transform/client/visitors Fragment.js

100% Statements 274/274
98.5% Branches 66/67
100% Functions 8/8
100% Lines 267/267

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 2682x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 167x 167x 3987x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 4155x 226x 226x 3987x 4155x 251x 251x 251x 3987x 3987x 3987x 3987x 3987x 3987x 2604x 2604x 103x 103x 103x 103x 103x 103x 103x 2604x 2604x 3987x 3987x 4155x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 1684x 6x 6x 1684x 1684x 1684x 1684x 1684x 4155x 32x 32x 2303x 147x 147x 147x 147x 147x 147x 147x 2271x 2102x 2102x 2102x 2102x 2102x 2102x 2102x 168x 168x 168x 168x 168x 168x 168x 168x 168x 168x 2102x 1934x 371x 371x 1934x 1563x 1563x 1563x 1563x 1563x 1563x 1563x 1563x 5x 5x 1562x 1563x 642x 642x 1562x 920x 920x 920x 920x 1562x 1562x 1562x 1933x 1933x 1933x 2124x 22x 22x 3986x 4153x 1303x 1303x 3986x 3986x 3986x 4137x 3561x 3561x 3561x 3561x 3561x 3986x 3986x 3986x 2x 2x 2x 2x 2604x 2604x 2604x 2604x 2604x 17857x 17853x 17857x 4x 4x 4x 17857x 2604x 2604x 2608x 2608x 2604x 2604x 2604x 2604x 2604x 2x 2x 2x 2x 2x 2x 2x 2604x 2604x 2604x 2604x 44x 44x 2604x 2560x 2560x 2555x 2604x 2604x 2x 2x 2x 2x 104x 104x 104x 126x 126x 126x 1x 1x 126x 126x 104x 104x 104x  
/** @import { Expression, Identifier, Statement } from 'estree' */
/** @import { AST, Namespace } from '#compiler' */
/** @import { SourceLocation } from '#shared' */
/** @import { ComponentClientTransformState, ComponentContext } from '../types' */
import { TEMPLATE_FRAGMENT, TEMPLATE_USE_IMPORT_NODE } from '../../../../../constants.js';
import { dev } from '../../../../state.js';
import * as b from '../../../../utils/builders.js';
import { sanitize_template_string } from '../../../../utils/sanitize_template_string.js';
import { clean_nodes, infer_namespace } from '../../utils.js';
import { process_children } from './shared/fragment.js';
import { build_render_statement } from './shared/utils.js';
 
/**
 * @param {AST.Fragment} node
 * @param {ComponentContext} context
 */
export function Fragment(node, context) {
	// Creates a new block which looks roughly like this:
	// ```js
	// // hoisted:
	// const block_name = $.template(`...`);
	//
	// // for the main block:
	// const id = block_name();
	// // init stuff and possibly render effect
	// $.append($$anchor, id);
	// ```
	// Adds the hoisted parts to `context.state.hoisted` and returns the statements of the main block.
 
	const parent = context.path.at(-1) ?? node;
 
	const namespace = infer_namespace(context.state.metadata.namespace, parent, node.nodes);
 
	const { hoisted, trimmed, is_standalone, is_text_first } = clean_nodes(
		parent,
		node.nodes,
		context.path,
		namespace,
		context.state,
		context.state.preserve_whitespace,
		context.state.options.preserveComments
	);
 
	if (hoisted.length === 0 && trimmed.length === 0) {
		return b.block([]);
	}
 
	const is_single_element = trimmed.length === 1 && trimmed[0].type === 'RegularElement';
	const is_single_child_not_needing_template =
		trimmed.length === 1 &&
		(trimmed[0].type === 'SvelteFragment' || trimmed[0].type === 'TitleElement');
 
	const template_name = context.state.scope.root.unique('root'); // TODO infer name from parent
 
	/** @type {Statement[]} */
	const body = [];
 
	/** @type {Statement | undefined} */
	let close = undefined;
 
	/** @type {ComponentClientTransformState} */
	const state = {
		...context.state,
		before_init: [],
		init: [],
		update: [],
		after_update: [],
		template: [],
		locations: [],
		transform: { ...context.state.transform },
		metadata: {
			context: {
				template_needs_import_node: false,
				template_contains_script_tag: false
			},
			namespace,
			bound_contenteditable: context.state.metadata.bound_contenteditable
		}
	};
 
	for (const node of hoisted) {
		context.visit(node, state);
	}
 
	if (is_text_first) {
		// skip over inserted comment
		body.push(b.stmt(b.call('$.next')));
	}
 
	/**
	 * @param {Identifier} template_name
	 * @param {Expression[]} args
	 */
	const add_template = (template_name, args) => {
		let call = b.call(get_template_function(namespace, state), ...args);
		if (dev) {
			call = b.call(
				'$.add_locations',
				call,
				b.member(b.id(context.state.analysis.name), '$.FILENAME', true),
				build_locations(state.locations)
			);
		}
 
		context.state.hoisted.push(b.var(template_name, call));
	};
 
	if (is_single_element) {
		const element = /** @type {AST.RegularElement} */ (trimmed[0]);
 
		const id = b.id(context.state.scope.generate(element.name));
 
		context.visit(element, {
			...state,
			node: id
		});
 
		/** @type {Expression[]} */
		const args = [join_template(state.template)];
 
		if (state.metadata.context.template_needs_import_node) {
			args.push(b.literal(TEMPLATE_USE_IMPORT_NODE));
		}
 
		add_template(template_name, args);
 
		body.push(b.var(id, b.call(template_name)), ...state.before_init, ...state.init);
		close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
	} else if (is_single_child_not_needing_template) {
		context.visit(trimmed[0], state);
		body.push(...state.before_init, ...state.init);
	} else if (trimmed.length === 1 && trimmed[0].type === 'Text') {
		const id = b.id(context.state.scope.generate('text'));
		body.push(
			b.var(id, b.call('$.text', b.literal(trimmed[0].data))),
			...state.before_init,
			...state.init
		);
		close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
	} else if (trimmed.length > 0) {
		const id = b.id(context.state.scope.generate('fragment'));
 
		const use_space_template =
			trimmed.some((node) => node.type === 'ExpressionTag') &&
			trimmed.every((node) => node.type === 'Text' || node.type === 'ExpressionTag');
 
		if (use_space_template) {
			// special case — we can use `$.text` instead of creating a unique template
			const id = b.id(context.state.scope.generate('text'));
 
			process_children(trimmed, () => id, false, {
				...context,
				state
			});
 
			body.push(b.var(id, b.call('$.text')), ...state.before_init, ...state.init);
			close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
		} else {
			if (is_standalone) {
				// no need to create a template, we can just use the existing block's anchor
				process_children(trimmed, () => b.id('$$anchor'), false, { ...context, state });
			} else {
				/** @type {(is_text: boolean) => Expression} */
				const expression = (is_text) => b.call('$.first_child', id, is_text && b.true);
 
				process_children(trimmed, expression, false, { ...context, state });
 
				let flags = TEMPLATE_FRAGMENT;
 
				if (state.metadata.context.template_needs_import_node) {
					flags |= TEMPLATE_USE_IMPORT_NODE;
				}
 
				if (state.template.length === 1 && state.template[0] === '<!>') {
					// special case — we can use `$.comment` instead of creating a unique template
					body.push(b.var(id, b.call('$.comment')));
				} else {
					add_template(template_name, [join_template(state.template), b.literal(flags)]);
 
					body.push(b.var(id, b.call(template_name)));
				}
 
				close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
			}
 
			body.push(...state.before_init, ...state.init);
		}
	} else {
		body.push(...state.before_init, ...state.init);
	}
 
	if (state.update.length > 0) {
		body.push(build_render_statement(state.update));
	}
 
	body.push(...state.after_update);
 
	if (close !== undefined) {
		// It's important that close is the last statement in the block, as any previous statements
		// could contain element insertions into the template, which the close statement needs to
		// know of when constructing the list of current inner elements.
		body.push(close);
	}
 
	return b.block(body);
}
 
/**
 * @param {Array<string | Expression>} items
 */
function join_template(items) {
	let quasi = b.quasi('');
	const template = b.template([quasi], []);
 
	for (const item of items) {
		if (typeof item === 'string') {
			quasi.value.cooked += item;
		} else {
			template.expressions.push(item);
			template.quasis.push((quasi = b.quasi('')));
		}
	}
 
	for (const quasi of template.quasis) {
		quasi.value.raw = sanitize_template_string(/** @type {string} */ (quasi.value.cooked));
	}
 
	quasi.tail = true;
 
	return template;
}
 
/**
 *
 * @param {Namespace} namespace
 * @param {ComponentClientTransformState} state
 * @returns
 */
function get_template_function(namespace, state) {
	const contains_script_tag = state.metadata.context.template_contains_script_tag;
	return namespace === 'svg'
		? contains_script_tag
			? '$.svg_template_with_script'
			: '$.ns_template'
		: namespace === 'mathml'
			? '$.mathml_template'
			: contains_script_tag
				? '$.template_with_script'
				: '$.template';
}
 
/**
 * @param {SourceLocation[]} locations
 */
function build_locations(locations) {
	return b.array(
		locations.map((loc) => {
			const expression = b.array([b.literal(loc[0]), b.literal(loc[1])]);
 
			if (loc.length === 3) {
				expression.elements.push(build_locations(loc[2]));
			}
 
			return expression;
		})
	);
}