All files / renderer updateNodes.ts

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import areEquivalentValues from "./areEquivalentValues";
import { createNodes } from "./createNodes";
import { mountNodes } from "./mountNodes";
import { NodePatchingData } from "./NodePatcher";
 
export function updateNodes(container: Node, oldPatchingData: NodePatchingData | NodePatchingData[], newPatchingData: NodePatchingData | NodePatchingData[]) {
 
    if (Array.isArray(newPatchingData)) {
 
        updateArrayNodes(container, oldPatchingData as NodePatchingData[], newPatchingData);
    }
    else {
 
        let {
            node
        } = oldPatchingData as NodePatchingData;
 
        if (node === undefined) {
 
            throw new Error('There must be an existing node');
        }
 
        const {
            patcher: oldPatcher,
            values: oldValues,
            rules
        } = oldPatchingData as NodePatchingData;
 
        const {
            patcher,
            values
        } = newPatchingData;
 
        if (oldPatcher === patcher) {
 
            newPatchingData.rules = rules; // Set the compiled rules in the new patched data
 
            newPatchingData.node = node; // Set the node in the new patching data
 
            if (areEquivalentValues(oldPatchingData.values, newPatchingData.values)) {
 
                return; // Same patcher and same vales mean no changes to apply
            }
 
            oldPatcher.patchNode(node, rules, oldValues, values);
 
            (node as any)._$patchingData = newPatchingData;
        }
        else { // Different type of node, replace it with a new one
 
            const newNode = createNodes(newPatchingData);
 
            container.replaceChild(newNode, node);
        }
    }
}
 
function updateArrayNodes(container: Node, oldPatchingData: NodePatchingData[], newPatchingData: NodePatchingData[]) {
 
    let { length: oldCount } = oldPatchingData;
 
    // Map the keyed nodes from the old children nodes
    const keyedNodes = new Map<any, Node>();
 
    for (let i = 0; i < oldCount; ++i) {
 
        const {
            node: oldChild
        } = oldPatchingData[i];
 
        if (oldChild === undefined) { // Not a patching data
 
            continue;
        }
 
        let key = (oldChild as HTMLElement).getAttribute?.('key') || null;
 
        if (key !== null) {
 
            keyedNodes.set(key, oldChild);
        }
    }
 
    const { length: newCount } = newPatchingData;
 
    for (let i = 0; i < newCount; ++i) {
 
        const oldChild = i < oldPatchingData.length ?
            oldPatchingData[i].node :
            undefined;
 
        if (oldChild === undefined) { // Mount the child
 
            mountNodes(container, newPatchingData[i]);
        }
        else { // oldChild !== undefined
 
            const newChildPatchingData = newPatchingData[i];
 
            const {
                patcher,
                values
            } = newChildPatchingData;
 
            // Check for any keyed patching data
            const {
                keyIndex
            } = patcher;
 
            const valueKey = keyIndex !== undefined ? values[keyIndex].toString() : null;
 
            // Compare against a keyed node
            const oldChildKey = (oldChild as HTMLElement).getAttribute?.('key') || null;
 
            if (oldChildKey === valueKey) { // If the keys are the same patch the node with that patching data    
 
                updateNodes(oldChild, oldPatchingData[i], newChildPatchingData);
            }
            else { // oldChildKey !== valueKey - Find the node that corresponds with the keyed patching data
 
                if (keyedNodes.has(valueKey)) { // Find an existing keyed node
 
                    const keyedNode = keyedNodes.get(valueKey);
 
                    // If the values of the keyed node match the ones of the oldChild then just swap them
                    if (areEquivalentValues(newChildPatchingData.values, (keyedNode as any)._$patchingData.values)) {
 
                        if (i >= container.childNodes.length) {
 
                            container.appendChild(keyedNode);
                        }
                        else {
 
                            container.insertBefore(keyedNode, container.childNodes[i]); // Notice oldNode is not being used since its position might have changed
                        }
 
                        newChildPatchingData.node = keyedNode; // Set the node of the new patching data
                    }
                    else { // Some value has changed, patch the existing node
 
                        updateNodes(oldChild, oldPatchingData[i], (keyedNode as any)._$patchingData);
                    }
                }
                else { // No keyed node found, set the new child
 
                    updateNodes(oldChild, oldPatchingData[i], newChildPatchingData);
                }
            }
        }
    }
 
    // Remove the extra nodes
    for (let i = oldCount - 1; i >= newCount; --i) {
 
        (oldPatchingData[i].node as HTMLElement).remove();
    }
}