clone.js — svelte Source File

Source Code

/** @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]
 * @param {boolean} [no_tojson]
 * @returns {Snapshot<T>}
 */
export function snapshot(value, skip_warning = false, no_tojson = false) {
	if (DEV && !skip_warning) {
		/** @type {string[]} */
		const paths = [];

		const copy = clone(value, new Map(), '', paths, null, no_tojson);
		if (paths.length === 1 && paths[0] === '') {
			// value could not be cloned
			w.state_snapshot_uncloneable();
		} else if (paths.length > 0) {
			// 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, null, no_tojson);
}

/**
 * @template T
 * @param {T} value
 * @param {Map<T, Snapshot<T>>} cloned
 * @param {string} path
 * @param {string[]} paths
 * @param {null | T} [original] The original value, if `value` was produced from a `toJSON` call
 * @param {boolean} [no_tojson]
 * @returns {Snapshot<T>}
 */
function clone(value, cloned, path, paths, original = null, no_tojson = false) {
	if (typeof value === 'object' && value !== null) {
		var unwrapped = cloned.get(value);
		if (unwrapped !== undefined) return unwrapped;
// ... (78 more lines)