Create Tree Structure from list of nodes with parent property

list_nodes_to_tree.js

const idMapping = data.reduce((acc, el, i) => {
    acc[el.id] = i;
    return acc;
}, {});

let root = [];
data.forEach(el => {
    // Handle the root element
    if (el.parent === null) {
        root.push(el);
        return;
    }
    // Use our mapping to locate the parent element in our data array
    const parentEl = data[idMapping[el.parent]];
    // Add our current el to its parent's `nodes` array
    if (parentEl && parentEl.hasOwnProperty('parent'))
        parentEl.nodes = [...(parentEl.nodes || []), el];
});

// Source: https://typeofnan.dev/an-easy-way-to-build-a-tree-with-object-references/