All files / src/internal/shared clone.js

94.73% Statements 108/114
85.71% Branches 30/35
100% Functions 2/2
94.59% Lines 105/111

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 1122x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 67x 67x 67x 67x 67x 67x 1x 1x 67x 2x 2x 2x 2x 2x 2x 2x 2x 2x 67x 67x 67x       2x 2x 2x 2x 2x 2x 2x 2x 2x 307x 307x 126x 126x 121x 126x 73x 73x 73x 73x 187x 187x 73x 73x 73x 48x 126x 43x 43x 43x 43x 43x 52x 52x 52x 43x 43x 43x 5x 16x 2x 2x 3x 14x 1x 1x 1x 1x 1x 1x 1x 126x 183x 307x       183x 183x 183x 307x 113x 113x 113x 113x 113x 113x 307x  
/** @import { Snapshot } from './types' */
import { DEV } from 'esm-env';
import * as w from './warnings.js';
import { get_prototype_of, is_array, object_prototype } from './utils.js';
 
/**
 * In dev, we keep track of which properties could not be cloned. In prod
 * we don't bother, but we keep a dummy array around so that the
 * signature stays the same
 * @type {string[]}
 */
const empty = [];
 
/**
 * @template T
 * @param {T} value
 * @param {boolean} [skip_warning]
 * @returns {Snapshot<T>}
 */
export function snapshot(value, skip_warning = false) {
	if (DEV) {
		/** @type {string[]} */
		const paths = [];
 
		const copy = clone(value, new Map(), '', paths);
		if (paths.length === 1 && paths[0] === '' && !skip_warning) {
			// value could not be cloned
			w.state_snapshot_uncloneable();
		} else if (paths.length > 0 && !skip_warning) {
			// some properties could not be cloned
			const slice = paths.length > 10 ? paths.slice(0, 7) : paths.slice(0, 10);
			const excess = paths.length - slice.length;
 
			let uncloned = slice.map((path) => `- <value>${path}`).join('\n');
			if (excess > 0) uncloned += `\n- ...and ${excess} more`;
 
			w.state_snapshot_uncloneable(uncloned);
		}
 
		return copy;
	}

	return clone(value, new Map(), '', empty);
}
 
/**
 * @template T
 * @param {T} value
 * @param {Map<T, Snapshot<T>>} cloned
 * @param {string} path
 * @param {string[]} paths
 * @returns {Snapshot<T>}
 */
function clone(value, cloned, path, paths) {
	if (typeof value === 'object' && value !== null) {
		const unwrapped = cloned.get(value);
		if (unwrapped !== undefined) return unwrapped;
 
		if (is_array(value)) {
			const copy = /** @type {Snapshot<any>} */ ([]);
			cloned.set(value, copy);
 
			for (let i = 0; i < value.length; i += 1) {
				copy.push(clone(value[i], cloned, DEV ? `${path}[${i}]` : path, paths));
			}
 
			return copy;
		}
 
		if (get_prototype_of(value) === object_prototype) {
			/** @type {Snapshot<any>} */
			const copy = {};
			cloned.set(value, copy);
 
			for (var key in value) {
				// @ts-expect-error
				copy[key] = clone(value[key], cloned, DEV ? `${path}.${key}` : path, paths);
			}
 
			return copy;
		}
 
		if (value instanceof Date) {
			return /** @type {Snapshot<T>} */ (structuredClone(value));
		}
 
		if (typeof (/** @type {T & { toJSON?: any } } */ (value).toJSON) === 'function') {
			return clone(
				/** @type {T & { toJSON(): any } } */ (value).toJSON(),
				cloned,
				DEV ? `${path}.toJSON()` : path,
				paths
			);
		}
	}
 
	if (value instanceof EventTarget) {
		// can't be cloned
		return /** @type {Snapshot<T>} */ (value);
	}
 
	try {
		return /** @type {Snapshot<T>} */ (structuredClone(value));
	} catch (e) {
		if (DEV) {
			paths.push(path);
		}
 
		return /** @type {Snapshot<T>} */ (value);
	}
}