All files / src/internal/client proxy.js

97.45% Statements 306/314
97.02% Branches 98/101
91.66% Functions 11/12
97.38% Lines 298/306

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 3132x 2x 2x             2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 3230x 3230x 1410x 1410x 1820x 1820x 1820x 3230x 52x 52x 1768x 1768x 1768x 1768x 1768x 1768x 3230x 627x 627x 627x 627x 1768x 1768x 1768x 1768x 1768x 1768x 1768x 1768x 1768x 1768x 1768x 14x 14x 14x 14x 14x 1768x 1754x 1754x 1754x 1076x 1076x 1754x 1754x 1768x 1768x 1768x 1768x 3x 3x 3x 3x 2x 3x 1x 1x 1x 1x 1x 1x 2x 2x 2x 2x 2x 2x 3x     2x 2x 1768x 1768x 1768x 33x 33x 33x 2x 1x 1x 33x 31x 31x 31x 33x 33x 1768x 1768x 1768x 4367x 97x 97x 4270x 4367x 24x 24x 4246x 4246x 4246x 4246x 4246x 4367x 766x 766x 766x 4246x 4367x 3892x 3892x 3892x 354x 354x 1768x 1768x 1768x 227x 227x 227x 206x 206x 226x 21x 21x 21x 21x 5x 5x 5x 5x 5x 5x 5x 21x 222x 222x 1768x 1768x 1768x 290x     290x 290x 106x 106x 184x 184x 290x 290x 290x 290x 16x 290x 179x 11x 11x 11x 179x 179x 179x     179x 184x 184x 1768x 1768x 1768x 1018x 1018x 1018x 1018x 1018x 110x 36x 36x 33x 36x 3x 3x 3x 3x 3x 3x 36x 110x 1018x 1018x 1018x 1018x 1018x 1018x 100x 94x 94x 94x 94x 1018x 918x 918x 918x 1018x 1018x 1018x 1018x 1018x 4x 4x 1018x 1018x 1018x 1018x 1018x 1018x 1018x 6x 6x 1018x 1018x 118x 118x 118x 118x 118x 92x 92x 92x 92x 92x 92x 92x 118x 118x 118x 1018x 1018x 1768x 1768x 1768x 264x 264x 264x 192x 192x 264x 264x 264x 154x 4x 4x 154x 264x 264x 1768x 1768x 1768x     1768x 1768x 2x 2x 2x 2x 2x 149x 149x 149x 2x 2x 2x 2x 2x 1814282x 10x 10x 1814272x 1814272x 1814272x 2x 2x 2x 2x 2x 2x 568x 568x  
/** @import { ProxyMetadata, ProxyStateObject, Source } from '#client' */
import { DEV } from 'esm-env';
import { get, current_component_context, untrack, current_effect } from './runtime.js';
import {
	array_prototype,
	get_descriptor,
	get_prototype_of,
	is_array,
	object_prototype
} from '../shared/utils.js';
import { check_ownership, widen_ownership } from './dev/ownership.js';
import { source, set } from './reactivity/sources.js';
import { STATE_SYMBOL, STATE_SYMBOL_METADATA } from './constants.js';
import { UNINITIALIZED } from '../../constants.js';
import * as e from './errors.js';
 
/**
 * @template T
 * @param {T} value
 * @param {ProxyMetadata | null} [parent]
 * @param {Source<T>} [prev] dev mode only
 * @returns {T}
 */
export function proxy(value, parent = null, prev) {
	// if non-proxyable, or is already a proxy, return `value`
	if (typeof value !== 'object' || value === null || STATE_SYMBOL in value) {
		return value;
	}
 
	const prototype = get_prototype_of(value);
 
	if (prototype !== object_prototype && prototype !== array_prototype) {
		return value;
	}
 
	/** @type {Map<any, Source<any>>} */
	var sources = new Map();
	var is_proxied_array = is_array(value);
	var version = source(0);
 
	if (is_proxied_array) {
		// We need to create the length source eagerly to ensure that
		// mutations to the array are properly synced with our proxy
		sources.set('length', source(/** @type {any[]} */ (value).length));
	}
 
	/** @type {ProxyMetadata} */
	var metadata;
 
	if (DEV) {
		metadata = {
			parent,
			owners: null
		};
 
		if (prev) {
			// Reuse owners from previous state; necessary because reassignment is not guaranteed to have correct component context.
			// If no previous proxy exists we play it safe and assume ownerless state
			// @ts-expect-error
			const prev_owners = prev.v?.[STATE_SYMBOL_METADATA]?.owners;
			metadata.owners = prev_owners ? new Set(prev_owners) : null;
		} else {
			metadata.owners =
				parent === null
					? current_component_context !== null
						? new Set([current_component_context.function])
						: null
					: new Set();
		}
	}
 
	return new Proxy(/** @type {any} */ (value), {
		defineProperty(_, prop, descriptor) {
			if (
				!('value' in descriptor) ||
				descriptor.configurable === false ||
				descriptor.enumerable === false ||
				descriptor.writable === false
			) {
				// we disallow non-basic descriptors, because unless they are applied to the
				// target object — which we avoid, so that state can be forked — we will run
				// afoul of the various invariants
				// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/getOwnPropertyDescriptor#invariants
				e.state_descriptors_fixed();
			}
 
			var s = sources.get(prop);
 
			if (s === undefined) {
				s = source(descriptor.value);
				sources.set(prop, s);
			} else {
				set(s, proxy(descriptor.value, metadata));
			}
 
			return true;
		},
 
		deleteProperty(target, prop) {
			var s = sources.get(prop);
 
			if (s === undefined) {
				if (prop in target) {
					sources.set(prop, source(UNINITIALIZED));
				}
			} else {
				set(s, UNINITIALIZED);
				update_version(version);
			}
 
			return true;
		},
 
		get(target, prop, receiver) {
			if (DEV && prop === STATE_SYMBOL_METADATA) {
				return metadata;
			}
 
			if (prop === STATE_SYMBOL) {
				return value;
			}
 
			var s = sources.get(prop);
			var exists = prop in target;
 
			// create a source, but only if it's an own property and not a prototype property
			if (s === undefined && (!exists || get_descriptor(target, prop)?.writable)) {
				s = source(proxy(exists ? target[prop] : UNINITIALIZED, metadata));
				sources.set(prop, s);
			}
 
			if (s !== undefined) {
				var v = get(s);
				return v === UNINITIALIZED ? undefined : v;
			}
 
			return Reflect.get(target, prop, receiver);
		},
 
		getOwnPropertyDescriptor(target, prop) {
			var descriptor = Reflect.getOwnPropertyDescriptor(target, prop);
 
			if (descriptor && 'value' in descriptor) {
				var s = sources.get(prop);
				if (s) descriptor.value = get(s);
			} else if (descriptor === undefined) {
				var source = sources.get(prop);
				var value = source?.v;
 
				if (source !== undefined && value !== UNINITIALIZED) {
					return {
						enumerable: true,
						configurable: true,
						value,
						writable: true
					};
				}
			}
 
			return descriptor;
		},
 
		has(target, prop) {
			if (DEV && prop === STATE_SYMBOL_METADATA) {
				return true;
			}
 
			if (prop === STATE_SYMBOL) {
				return true;
			}
 
			var s = sources.get(prop);
			var has = (s !== undefined && s.v !== UNINITIALIZED) || Reflect.has(target, prop);
 
			if (
				s !== undefined ||
				(current_effect !== null && (!has || get_descriptor(target, prop)?.writable))
			) {
				if (s === undefined) {
					s = source(has ? proxy(target[prop], metadata) : UNINITIALIZED);
					sources.set(prop, s);
				}
 
				var value = get(s);
				if (value === UNINITIALIZED) {
					return false;
				}
			}
 
			return has;
		},
 
		set(target, prop, value, receiver) {
			var s = sources.get(prop);
			var has = prop in target;
 
			// variable.length = value -> clear all signals with index >= value
			if (is_proxied_array && prop === 'length') {
				for (var i = value; i < /** @type {Source<number>} */ (s).v; i += 1) {
					var other_s = sources.get(i + '');
					if (other_s !== undefined) {
						set(other_s, UNINITIALIZED);
					} else if (i in target) {
						// If the item exists in the original, we need to create a uninitialized source,
						// else a later read of the property would result in a source being created with
						// the value of the original item at that index.
						other_s = source(UNINITIALIZED);
						sources.set(i + '', other_s);
					}
				}
			}
 
			// If we haven't yet created a source for this property, we need to ensure
			// we do so otherwise if we read it later, then the write won't be tracked and
			// the heuristics of effects will be different vs if we had read the proxied
			// object property before writing to that property.
			if (s === undefined) {
				if (!has || get_descriptor(target, prop)?.writable) {
					s = source(undefined);
					set(s, proxy(value, metadata));
					sources.set(prop, s);
				}
			} else {
				has = s.v !== UNINITIALIZED;
				set(s, proxy(value, metadata));
			}
 
			if (DEV) {
				/** @type {ProxyMetadata | undefined} */
				var prop_metadata = value?.[STATE_SYMBOL_METADATA];
				if (prop_metadata && prop_metadata?.parent !== metadata) {
					widen_ownership(metadata, prop_metadata);
				}
				check_ownership(metadata);
			}
 
			var descriptor = Reflect.getOwnPropertyDescriptor(target, prop);
 
			// Set the new value before updating any signals so that any listeners get the new value
			if (descriptor?.set) {
				descriptor.set.call(receiver, value);
			}
 
			if (!has) {
				// If we have mutated an array directly, we might need to
				// signal that length has also changed. Do it before updating metadata
				// to ensure that iterating over the array as a result of a metadata update
				// will not cause the length to be out of sync.
				if (is_proxied_array && typeof prop === 'string') {
					var ls = /** @type {Source<number>} */ (sources.get('length'));
					var n = Number(prop);
 
					if (Number.isInteger(n) && n >= ls.v) {
						set(ls, n + 1);
					}
				}
 
				update_version(version);
			}
 
			return true;
		},
 
		ownKeys(target) {
			get(version);
 
			var own_keys = Reflect.ownKeys(target).filter((key) => {
				var source = sources.get(key);
				return source === undefined || source.v !== UNINITIALIZED;
			});
 
			for (var [key, source] of sources) {
				if (source.v !== UNINITIALIZED && !(key in target)) {
					own_keys.push(key);
				}
			}
 
			return own_keys;
		},
 
		setPrototypeOf() {
			e.state_prototype_fixed();
		}
	});
}
 
/**
 * @param {Source<number>} signal
 * @param {1 | -1} [d]
 */
function update_version(signal, d = 1) {
	set(signal, signal.v + d);
}
 
/**
 * @param {any} value
 */
export function get_proxied_value(value) {
	if (value !== null && typeof value === 'object' && STATE_SYMBOL in value) {
		return value[STATE_SYMBOL];
	}
 
	return value;
}
 
/**
 * @param {any} a
 * @param {any} b
 */
export function is(a, b) {
	return Object.is(get_proxied_value(a), get_proxied_value(b));
}