All files / src/internal/client/dom hydration.js

100% Statements 102/102
100% Branches 21/21
100% Functions 4/4
100% Lines 99/99

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 1002x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 4562x 4562x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 1567x 1567x 1567x 2x 2x 2x 2x 2x 2x 2x 5815x 5815x 5815x 5815x 2x 2x 2x 2x 2x 2x 2x 2x 2x 12943x 6291x 6291x 6652x 6652x 6652x 6652x 12943x 8x 8x 6644x 6644x 6644x 6644x 6644x 12943x 40308x 26937x 26937x 26937x 10096x 26937x 16738x 6642x 6642x 6642x 6642x 10096x 10096x 10096x 26937x 33666x 33666x 33666x 2x 2x 2x 2x 2x 2x 2x 1x 1x 2x 2x 2x 2x 2x  
import { DEV } from 'esm-env';
import { HYDRATION_END, HYDRATION_START, HYDRATION_ERROR } from '../../../constants.js';
import * as w from '../warnings.js';
 
/**
 * Use this variable to guard everything related to hydration code so it can be treeshaken out
 * if the user doesn't use the `hydrate` method and these code paths are therefore not needed.
 */
export let hydrating = false;
 
/** @param {boolean} value */
export function set_hydrating(value) {
	hydrating = value;
}
 
/**
 * Array of nodes to traverse for hydration. This will be null if we're not hydrating, but for
 * the sake of simplicity we're not going to use `null` checks everywhere and instead rely on
 * the `hydrating` flag to tell whether or not we're in hydration mode at which point this is set.
 * @type {import('#client').TemplateNode[]}
 */
export let hydrate_nodes = /** @type {any} */ (null);
 
/** @type {import('#client').TemplateNode} */
export let hydrate_start;
 
/** @param {import('#client').TemplateNode[]} nodes */
export function set_hydrate_nodes(nodes) {
	hydrate_nodes = nodes;
	hydrate_start = nodes && nodes[0];
}
 
/**
 * When assigning nodes to an effect during hydration, we typically want the hydration boundary comment node
 * immediately before `hydrate_start`. In some cases, this comment doesn't exist because we optimized it away.
 * TODO it might be worth storing this value separately rather than retrieving it with `previousSibling`
 */
export function get_start() {
	return /** @type {import('#client').TemplateNode} */ (
		hydrate_start.previousSibling ?? hydrate_start
	);
}
 
/**
 * This function is only called when `hydrating` is true. If passed a `<!--[-->` opening
 * hydration marker, it finds the corresponding closing marker and sets `hydrate_nodes`
 * to everything between the markers, before returning the closing marker.
 * @param {Node} node
 * @returns {Node}
 */
export function hydrate_anchor(node) {
	if (node.nodeType !== 8) {
		return node;
	}
 
	var current = /** @type {Node | null} */ (node);
 
	// TODO this could have false positives, if a user comment consisted of `[`. need to tighten that up
	if (/** @type {Comment} */ (current).data !== HYDRATION_START) {
		return node;
	}
 
	/** @type {Node[]} */
	var nodes = [];
	var depth = 0;
 
	while ((current = /** @type {Node} */ (current).nextSibling) !== null) {
		if (current.nodeType === 8) {
			var data = /** @type {Comment} */ (current).data;
 
			if (data === HYDRATION_START) {
				depth += 1;
			} else if (data[0] === HYDRATION_END) {
				if (depth === 0) {
					hydrate_nodes = /** @type {import('#client').TemplateNode[]} */ (nodes);
					hydrate_start = /** @type {import('#client').TemplateNode} */ (nodes[0]);
					return current;
				}
 
				depth -= 1;
			}
		}
 
		nodes.push(current);
	}
 
	let location;
 
	if (DEV) {
		// @ts-expect-error
		const loc = node.parentNode?.__svelte_meta?.loc;
		if (loc) {
			location = `${loc.file}:${loc.line}:${loc.column}`;
		}
	}
 
	w.hydration_mismatch(location);
	throw HYDRATION_ERROR;
}