All files / src/compiler/phases/3-transform/server/visitors ClassBody.js

98.38% Statements 122/124
94.59% Branches 35/37
100% Functions 1/1
98.34% Lines 119/121

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 1222x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 51x 4x 4x 4x 47x 47x 47x 47x 47x 47x 47x 47x 47x 47x 47x 122x 122x 67x 122x 66x 66x 66x 66x 66x 66x 60x 60x 14x 14x 14x 14x 14x 14x 14x 14x 1x 14x 13x 13x 14x 60x 66x 122x 47x 47x 47x 13x 13x     13x 13x 13x 13x 47x 47x 47x 47x 47x 47x 47x 47x 122x 122x 67x 122x 66x 66x 66x 66x 66x 66x 14x 14x 14x 14x 14x 14x 14x 1x 14x 13x 13x 13x 13x 13x 13x 13x 13x 1x 1x 1x 1x 1x 1x 1x 1x 1x 13x 14x 14x 14x 66x 108x 108x 108x 47x 47x 47x  
/** @import { ClassBody, Expression, MethodDefinition, PropertyDefinition } from 'estree' */
/** @import { Context } from '../types.js' */
/** @import { StateField } from '../../client/types.js' */
import { dev } from '../../../../state.js';
import * as b from '../../../../utils/builders.js';
import { get_rune } from '../../../scope.js';
 
/**
 * @param {ClassBody} node
 * @param {Context} context
 */
export function ClassBody(node, context) {
	if (!context.state.analysis.runes) {
		context.next();
		return;
	}
 
	/** @type {Map<string, StateField>} */
	const public_derived = new Map();
 
	/** @type {Map<string, StateField>} */
	const private_derived = new Map();
 
	/** @type {string[]} */
	const private_ids = [];
 
	for (const definition of node.body) {
		if (
			definition.type === 'PropertyDefinition' &&
			(definition.key.type === 'Identifier' || definition.key.type === 'PrivateIdentifier')
		) {
			const { type, name } = definition.key;
 
			const is_private = type === 'PrivateIdentifier';
			if (is_private) private_ids.push(name);
 
			if (definition.value?.type === 'CallExpression') {
				const rune = get_rune(definition.value, context.state.scope);
				if (rune === '$derived' || rune === '$derived.by') {
					/** @type {StateField} */
					const field = {
						kind: rune === '$derived.by' ? 'derived_by' : 'derived',
						// @ts-expect-error this is set in the next pass
						id: is_private ? definition.key : null
					};
 
					if (is_private) {
						private_derived.set(name, field);
					} else {
						public_derived.set(name, field);
					}
				}
			}
		}
	}
 
	// each `foo = $derived()` needs a backing `#foo` field
	for (const [name, field] of public_derived) {
		let deconflicted = name;
		while (private_ids.includes(deconflicted)) {
			deconflicted = '_' + deconflicted;
		}
 
		private_ids.push(deconflicted);
		field.id = b.private_id(deconflicted);
	}
 
	/** @type {Array<MethodDefinition | PropertyDefinition>} */
	const body = [];
 
	const child_state = { ...context.state, private_derived };
 
	// Replace parts of the class body
	for (const definition of node.body) {
		if (
			definition.type === 'PropertyDefinition' &&
			(definition.key.type === 'Identifier' || definition.key.type === 'PrivateIdentifier')
		) {
			const name = definition.key.name;
 
			const is_private = definition.key.type === 'PrivateIdentifier';
			const field = (is_private ? private_derived : public_derived).get(name);
 
			if (definition.value?.type === 'CallExpression' && field !== undefined) {
				const init = /** @type {Expression} **/ (
					context.visit(definition.value.arguments[0], child_state)
				);
				const value =
					field.kind === 'derived_by' ? b.call('$.once', init) : b.call('$.once', b.thunk(init));
 
				if (is_private) {
					body.push(b.prop_def(field.id, value));
				} else {
					// #foo;
					const member = b.member(b.this, field.id);
					body.push(b.prop_def(field.id, value));
 
					// get foo() { return this.#foo; }
					body.push(b.method('get', definition.key, [], [b.return(b.call(member))]));
 
					if (dev && (field.kind === 'derived' || field.kind === 'derived_by')) {
						body.push(
							b.method(
								'set',
								definition.key,
								[b.id('_')],
								[b.throw_error(`Cannot update a derived property ('${name}')`)]
							)
						);
					}
				}
 
				continue;
			}
		}
 
		body.push(/** @type {MethodDefinition} **/ (context.visit(definition, child_state)));
	}
 
	return { ...node, body };
}