index.ts

import { b, x, p } from 'code-red';
import Component from '../Component';
import Renderer from './Renderer';
import { CompileOptions, CssResult } from '../../interfaces';
import { walk } from 'estree-walker';
import { extract_names, Scope } from 'periscopic';
import { invalidate } from './invalidate';
import Block from './Block';
import { ImportDeclaration, ClassDeclaration, FunctionExpression, Node, Statement, ObjectExpression, Expression } from 'estree';
import { apply_preprocessor_sourcemap } from '../../utils/mapped_code';
import { RawSourceMap, DecodedSourceMap } from '@ampproject/remapping/dist/types/types';
import { flatten } from '../../utils/flatten';
import check_enable_sourcemap from '../utils/check_enable_sourcemap';
import { push_array } from '../../utils/push_array';

export default function dom(
	component: Component,
	options: CompileOptions
): { js: Node[]; css: CssResult } {
	const { name } = component;

	const renderer = new Renderer(component, options);
	const { block } = renderer;

	block.has_outro_method = true;

	// prevent fragment being created twice (#1063)
	if (options.customElement) block.chunks.create.push(b`this.c = @noop;`);

	const body = [];

	if (renderer.file_var) {
		const file = component.file ? x`"${component.file}"` : x`undefined`;
		body.push(b`const ${renderer.file_var} = ${file};`);
	}

	const css = component.stylesheet.render(options.filename, !options.customElement);

	const css_sourcemap_enabled = check_enable_sourcemap(options.enableSourcemap, 'css');

	if (css_sourcemap_enabled) {
		css.map = apply_preprocessor_sourcemap(options.filename, css.map, options.sourcemap as string | RawSourceMap | DecodedSourceMap);
	} else {
		css.map = null;
	}

	const styles = css_sourcemap_enabled && component.stylesheet.has_styles && options.dev
		? `${css.code}\n/*# sourceMappingURL=${css.map.toUrl()} */`
		: css.code;

	const add_css = component.get_unique_name('add_css');

	const should_add_css = (
		!options.customElement &&
		!!styles &&
		options.css === 'injected'
	);

	if (should_add_css) {
		body.push(b`
			function ${add_css}(target) {
				@append_styles(target, "${component.stylesheet.id}", "${styles}");
			}
		`);
	}

	// fix order
	// TODO the deconflicted names of blocks are reversed... should set them here
	const blocks = renderer.blocks.slice().reverse();

	push_array(body, blocks.map(block => {
		// TODO this is a horrible mess — renderer.blocks
		// contains a mixture of Blocks and Nodes
		if ((block as Block).render) return (block as Block).render();
		return block;
	}));

	if (options.dev && !options.hydratable) {
		block.chunks.claim.push(
			b`throw new @_Error("options.hydrate only works if the component was compiled with the \`hydratable: true\` option");`
		);
	}

	const uses_slots = component.var_lookup.has('$$slots');
	let compute_slots;
	if (uses_slots) {
		compute_slots = b`
			const $$slots = @compute_slots(#slots);
		`;
	}


	const uses_props = component.var_lookup.has('$$props');
	const uses_rest = component.var_lookup.has('$$restProps');
	const $$props = uses_props || uses_rest ? '$$new_props' : '$$props';
	const props = component.vars.filter(variable => !variable.module && variable.export_name);
	const writable_props = props.filter(variable => variable.writable);

	const omit_props_names = component.get_unique_name('omit_props_names');
	const compute_rest = x`@compute_rest_props($$props, ${omit_props_names.name})`;
	const rest = uses_rest ? b`
		const ${omit_props_names.name} = [${props.map(prop => `"${prop.export_name}"`).join(',')}];
		let $$restProps = ${compute_rest};
	` : null;

	const set = (uses_props || uses_rest || writable_props.length > 0 || component.slots.size > 0)
		? x`
			${$$props} => {
				${uses_props && renderer.invalidate('$$props', x`$$props = @assign(@assign({}, $$props), @exclude_internal_props($$new_props))`)}
				${uses_rest && !uses_props && x`$$props = @assign(@assign({}, $$props), @exclude_internal_props($$new_props))`}
				${uses_rest && renderer.invalidate('$$restProps', x`$$restProps = ${compute_rest}`)}
				${writable_props.map(prop =>
					b`if ('${prop.export_name}' in ${$$props}) ${renderer.invalidate(prop.name, x`${prop.name} = ${$$props}.${prop.export_name}`)};`
				)}
				${component.slots.size > 0 &&
				b`if ('$$scope' in ${$$props}) ${renderer.invalidate('$$scope', x`$$scope = ${$$props}.$$scope`)};`}
			}
		`
		: null;

	const accessors = [];

	const not_equal = component.component_options.immutable ? x`@not_equal` : x`@safe_not_equal`;
	let missing_props_check: Node[] | Node;
	let inject_state: Expression;
	let capture_state: Expression;
	let props_inject: Node[] | Node;

	props.forEach(prop => {
		const variable = component.var_lookup.get(prop.name);

		if (!variable.writable || component.component_options.accessors) {
			accessors.push({
				type: 'MethodDefinition',
				kind: 'get',
				key: { type: 'Identifier', name: prop.export_name },
				value: x`function() {
					return ${prop.hoistable ? prop.name : x`this.$$.ctx[${renderer.context_lookup.get(prop.name).index}]`}
				}`
			});
		} else if (component.compile_options.dev) {
			accessors.push({
				type: 'MethodDefinition',
				kind: 'get',
				key: { type: 'Identifier', name: prop.export_name },
				value: x`function() {
					throw new @_Error("<${component.tag}>: Props cannot be read directly from the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
				}`
			});
		}

		if (component.component_options.accessors) {
			if (variable.writable && !renderer.readonly.has(prop.name)) {
				accessors.push({
					type: 'MethodDefinition',
					kind: 'set',
					key: { type: 'Identifier', name: prop.export_name },
					value: x`function(${prop.name}) {
						this.$$set({ ${prop.export_name}: ${prop.name} });
						@flush();
					}`
				});
			} else if (component.compile_options.dev) {
				accessors.push({
					type: 'MethodDefinition',
					kind: 'set',
					key: { type: 'Identifier', name: prop.export_name },
					value: x`function(value) {
						throw new @_Error("<${component.tag}>: Cannot set read-only property '${prop.export_name}'");
					}`
				});
			}
		} else if (component.compile_options.dev) {
			accessors.push({
				type: 'MethodDefinition',
				kind: 'set',
				key: { type: 'Identifier', name: prop.export_name },
				value: x`function(value) {
					throw new @_Error("<${component.tag}>: Props cannot be set directly on the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
				}`
			});
		}
	});

	component.instance_exports_from.forEach(exports_from => {
		const import_declaration = {
			...exports_from,
			type: 'ImportDeclaration',
			specifiers: [],
			source: exports_from.source
		};
		component.imports.push(import_declaration as ImportDeclaration);

		exports_from.specifiers.forEach(specifier => {
			if (component.component_options.accessors) {
				const name = component.get_unique_name(specifier.exported.name);
				import_declaration.specifiers.push({
					...specifier,
					type: 'ImportSpecifier',
					imported: specifier.local,
					local: name
				});

				accessors.push({
					type: 'MethodDefinition',
					kind: 'get',
					key: { type: 'Identifier', name: specifier.exported.name },
					value: x`function() {
						return ${name}
					}`
				});
			} else if (component.compile_options.dev) {
				accessors.push({
					type: 'MethodDefinition',
					kind: 'get',
					key: { type: 'Identifier', name: specifier.exported.name },
					value: x`function() {
						throw new @_Error("<${component.tag}>: Props cannot be read directly from the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
					}`
				});
			}
		});
	});

	if (component.compile_options.dev) {
		// checking that expected ones were passed
		const expected = props.filter(prop => prop.writable && !prop.initialised);

		if (expected.length) {
			missing_props_check = b`
				$$self.$$.on_mount.push(function () {
					${expected.map(prop => b`
					if (${prop.name} === undefined && !(('${prop.export_name}' in $$props) || $$self.$$.bound[$$self.$$.props['${prop.export_name}']])) {
						@_console.warn("<${component.tag}> was created without expected prop '${prop.export_name}'");
					}`)}
				});
			`;
		}

		const capturable_vars = component.vars.filter(v => !v.internal && !v.global && !v.name.startsWith('$$'));

		if (capturable_vars.length > 0) {
			capture_state = x`() => ({ ${capturable_vars.map(prop => p`${prop.name}`)} })`;
		}

		const injectable_vars = capturable_vars.filter(v => !v.module && v.writable && v.name[0] !== '$');

		if (uses_props || injectable_vars.length > 0) {
			inject_state = x`
				${$$props} => {
					${uses_props && renderer.invalidate('$$props', x`$$props = @assign(@assign({}, $$props), $$new_props)`)}
					${injectable_vars.map(
						v => b`if ('${v.name}' in $$props) ${renderer.invalidate(v.name, x`${v.name} = ${$$props}.${v.name}`)};`
					)}
				}
			`;

			props_inject = b`
				if ($$props && "$$inject" in $$props) {
					$$self.$inject_state($$props.$$inject);
				}
			`;
		}
	}

	// instrument assignments
	if (component.ast.instance) {
		let scope = component.instance_scope;
		const map = component.instance_scope_map;
		let execution_context: Node | null = null;

		walk(component.ast.instance.content, {
			enter(node: Node) {
				if (map.has(node)) {
					scope = map.get(node) as Scope;

					if (!execution_context && !scope.block) {
						execution_context = node;
					}
				} else if (!execution_context && node.type === 'LabeledStatement' && node.label.name === '$') {
					execution_context = node;
				}
			},

			leave(node: Node) {
				if (map.has(node)) {
					scope = scope.parent;
				}

				if (execution_context === node) {
					execution_context = null;
				}

				if (node.type === 'AssignmentExpression' || node.type === 'UpdateExpression') {
					const assignee = node.type === 'AssignmentExpression' ? node.left : node.argument;

					// normally (`a = 1`, `b.c = 2`), there'll be a single name
					// (a or b). In destructuring cases (`[d, e] = [e, d]`) there
					// may be more, in which case we need to tack the extra ones
					// onto the initial function call
					const names = new Set(extract_names(assignee as Node));

					this.replace(invalidate(renderer, scope, node, names, execution_context === null));
				}
			}
		});

		component.rewrite_props(({ name, reassigned, export_name }) => {
			const value = `$${name}`;
			const i = renderer.context_lookup.get(`$${name}`).index;

			const insert = (reassigned || export_name)
				? b`${`$$subscribe_${name}`}()`
				: b`@component_subscribe($$self, ${name}, #value => $$invalidate(${i}, ${value} = #value))`;

			if (component.compile_options.dev) {
				return b`@validate_store(${name}, '${name}'); ${insert}`;
			}

			return insert;
		});
	}

	const args = [x`$$self`];
	const has_invalidate = props.length > 0 ||
		component.has_reactive_assignments ||
		component.slots.size > 0 ||
		capture_state ||
		inject_state;
	if (has_invalidate) {
		args.push(x`$$props`, x`$$invalidate`);
	} else if (component.compile_options.dev) {
		// $$props arg is still needed for unknown prop check
		args.push(x`$$props`);
	}
	// has_create_fragment is intentionally to be true in dev mode.
	const has_create_fragment = component.compile_options.dev || block.has_content();
	if (has_create_fragment) {
		body.push(b`
			function create_fragment(#ctx) {
				${block.get_contents()}
			}
		`);
	}

	body.push(b`
		${component.extract_javascript(component.ast.module)}

		${component.fully_hoisted}
	`);

	const filtered_props = props.filter(prop => {
		const variable = component.var_lookup.get(prop.name);

		if (variable.hoistable) return false;
		return prop.name[0] !== '$';
	});

	const reactive_stores = component.vars.filter(variable => variable.name[0] === '$' && variable.name[1] !== '$');

	const instance_javascript = component.extract_javascript(component.ast.instance);

	const has_definition = (
		component.compile_options.dev ||
		(instance_javascript && instance_javascript.length > 0) ||
		filtered_props.length > 0 ||
		uses_props ||
		component.partly_hoisted.length > 0 ||
		renderer.initial_context.length > 0 ||
		component.reactive_declarations.length > 0 ||
		capture_state ||
		inject_state
	);

	const definition = has_definition
		? component.alias('instance')
		: { type: 'Literal', value: null };

	const reactive_store_subscriptions = reactive_stores
		.filter(store => {
			const variable = component.var_lookup.get(store.name.slice(1));
			return !variable || variable.hoistable;
		})
		.map(({ name }) => b`
			${component.compile_options.dev && b`@validate_store(${name.slice(1)}, '${name.slice(1)}');`}
			@component_subscribe($$self, ${name.slice(1)}, $$value => $$invalidate(${renderer.context_lookup.get(name).index}, ${name} = $$value));
		`);

	const resubscribable_reactive_store_unsubscribers = reactive_stores
		.filter(store => {
			const variable = component.var_lookup.get(store.name.slice(1));
			return variable && (variable.reassigned || variable.export_name);
		})
		.map(({ name }) => b`$$self.$$.on_destroy.push(() => ${`$$unsubscribe_${name.slice(1)}`}());`);

	if (has_definition) {
		const reactive_declarations: (Node | Node[]) = [];
		const fixed_reactive_declarations = []; // not really 'reactive' but whatever

		component.reactive_declarations.forEach(d => {
			const dependencies = Array.from(d.dependencies);
			const uses_rest_or_props = !!dependencies.find(n => n === '$$props' || n === '$$restProps');

			const writable = dependencies.filter(n => {
				const variable = component.var_lookup.get(n);
				return variable && (variable.export_name || variable.mutated || variable.reassigned);
			});

			const condition = !uses_rest_or_props && writable.length > 0 && renderer.dirty(writable, true);

			let statement = d.node; // TODO remove label (use d.node.body) if it's not referenced

			if (condition) statement = b`if (${condition}) { ${statement} }`[0] as Statement;

			if (condition || uses_rest_or_props) {
				reactive_declarations.push(statement);
			} else {
				fixed_reactive_declarations.push(statement);
			}
		});

		const injected = Array.from(component.injected_reactive_declaration_vars).filter(name => {
			const variable = component.var_lookup.get(name);
			return variable.injected && variable.name[0] !== '$';
		});

		const reactive_store_declarations = reactive_stores.map(variable => {
			const $name = variable.name;
			const name = $name.slice(1);

			const store = component.var_lookup.get(name);
			if (store && (store.reassigned || store.export_name)) {
				const unsubscribe = `$$unsubscribe_${name}`;
				const subscribe = `$$subscribe_${name}`;
				const i = renderer.context_lookup.get($name).index;

				return b`let ${$name}, ${unsubscribe} = @noop, ${subscribe} = () => (${unsubscribe}(), ${unsubscribe} = @subscribe(${name}, $$value => $$invalidate(${i}, ${$name} = $$value)), ${name})`;
			}

			return b`let ${$name};`;
		});

		let unknown_props_check;
		if (component.compile_options.dev && !(uses_props || uses_rest)) {
			unknown_props_check = b`
				const writable_props = [${writable_props.map(prop => x`'${prop.export_name}'`)}];
				@_Object.keys($$props).forEach(key => {
					if (!~writable_props.indexOf(key) && key.slice(0, 2) !== '$$' && key !== 'slot') @_console.warn(\`<${component.tag}> was created with unknown prop '\${key}'\`);
				});
			`;
		}

		const return_value = {
			type: 'ArrayExpression',
			elements: renderer.initial_context.map(member => ({
				type: 'Identifier',
				name: member.name
			}) as Expression)
		};

		body.push(b`
			function ${definition}(${args}) {
				${injected.map(name => b`let ${name};`)}

				${rest}

				${reactive_store_declarations}

				${reactive_store_subscriptions}

				${resubscribable_reactive_store_unsubscribers}

				${component.slots.size || component.compile_options.dev || uses_slots ? b`let { $$slots: #slots = {}, $$scope } = $$props;` : null}
				${component.compile_options.dev && b`@validate_slots('${component.tag}', #slots, [${[...component.slots.keys()].map(key => `'${key}'`).join(',')}]);`}
				${compute_slots}

				${instance_javascript}

				${missing_props_check}
				${unknown_props_check}

				${renderer.binding_groups.size > 0 && b`const $$binding_groups = [${[...renderer.binding_groups.keys()].map(_ => x`[]`)}];`}

				${component.partly_hoisted}

				${set && b`$$self.$$set = ${set};`}

				${capture_state && b`$$self.$capture_state = ${capture_state};`}

				${inject_state && b`$$self.$inject_state = ${inject_state};`}

				${/* before reactive declarations */ props_inject}

				${reactive_declarations.length > 0 && b`
				$$self.$$.update = () => {
					${reactive_declarations}
				};
				`}

				${fixed_reactive_declarations}

				${uses_props && b`$$props = @exclude_internal_props($$props);`}

				return ${return_value};
			}
		`);
	}

	const prop_indexes = x`{
		${props.filter(v => v.export_name && !v.module).map(v => p`${v.export_name}: ${renderer.context_lookup.get(v.name).index}`)}
	}` as ObjectExpression;

	let dirty;
	if (renderer.context_overflow) {
		dirty = x`[]`;
		for (let i = 0; i < renderer.context.length; i += 31) {
			dirty.elements.push(x`-1`);
		}
	}

	if (options.customElement) {

		let init_props = x`@attribute_to_object(this.attributes)`;
		if (uses_slots) {
			init_props = x`{ ...${init_props}, $$slots: @get_custom_elements_slots(this) }`;
		}

		const declaration = b`
			class ${name} extends @SvelteElement {
				constructor(options) {
					super();

					${css.code && b`this.shadowRoot.innerHTML = \`<style>${css.code.replace(/\\/g, '\\\\')}${css_sourcemap_enabled && options.dev ? `\n/*# sourceMappingURL=${css.map.toUrl()} */` : ''}</style>\`;`}

					@init(this, { target: this.shadowRoot, props: ${init_props}, customElement: true }, ${definition}, ${has_create_fragment ? 'create_fragment' : 'null'}, ${not_equal}, ${prop_indexes}, null, ${dirty});

					if (options) {
						if (options.target) {
							@insert(options.target, this, options.anchor);
						}

						${(props.length > 0 || uses_props || uses_rest) && b`
						if (options.props) {
							this.$set(options.props);
							@flush();
						}`}
					}
				}
			}
		`[0] as ClassDeclaration;

		if (props.length > 0) {
			declaration.body.body.push({
				type: 'MethodDefinition',
				kind: 'get',
				static: true,
				computed: false,
				key: { type: 'Identifier', name: 'observedAttributes' },
				value: x`function() {
					return [${props.map(prop => x`"${prop.export_name}"`)}];
				}` as FunctionExpression
			});
		}

		push_array(declaration.body.body, accessors);

		body.push(declaration);

		if (component.tag != null) {
			body.push(b`
				@_customElements.define("${component.tag}", ${name});
			`);
		}
	} else {
		const superclass = {
			type: 'Identifier',
			name: options.dev ? '@SvelteComponentDev' : '@SvelteComponent'
		};

		const optional_parameters = [];
		if (should_add_css) {
			optional_parameters.push(add_css);
		} else if (dirty) {
			optional_parameters.push(x`null`);
		}
		if (dirty) {
			optional_parameters.push(dirty);
		}

		const declaration = b`
			class ${name} extends ${superclass} {
				constructor(options) {
					super(${options.dev && 'options'});
					@init(this, options, ${definition}, ${has_create_fragment ? 'create_fragment' : 'null'}, ${not_equal}, ${prop_indexes}, ${optional_parameters});
					${options.dev && b`@dispatch_dev("SvelteRegisterComponent", { component: this, tagName: "${name.name}", options, id: create_fragment.name });`}
				}
			}
		`[0] as ClassDeclaration;

		push_array(declaration.body.body, accessors);

		body.push(declaration);
	}

	return { js: flatten(body), css };
}