Алгоритм развёртывания графа

const table = [
  {code: 'A', component: 'B1', amount: 1},
  {code: 'A', component: 'B2', amount: 1},
  {code: 'A', component: 'B3', amount: 1},
  {code: 'B1', component: null, amount: null},
  {code: 'B2', component: 'C1', amount: 1},
  {code: 'B2', component: 'C2', amount: 1},
  {code: 'B3', component: 'C3', amount: 1},
  {code: 'C1', component: null, amount: null},
  {code: 'C2', component: null, amount: null},
  {code: 'C3', component: null, amount: null},
];
 
v = 1;
 
const codesMap = {};
let parent, component
table.forEach(row => {
    if(!(parent = codesMap[row.code])) {
        parent = codesMap[row.code] = {code: row.code};
    }
 
    if(row.component) {
        if(!parent.components) parent.components = [];
        if(!(component = codesMap[row.component])) {
            component = codesMap[row.component] = {
                code: row.component, 
            };
        }
    component.isComponent = true;
        parent.components.push({
            component: component,
            amount: row.amount,
        })
    }
})
 
function showTree(thing, level, amount) {
 
    tree.innerHTML += '<div>' + '--'.repeat(level) + thing.code + (amount ? ' - ' + amount + 'шт.' : '') + '</div>';
    if(thing.components) {
        thing.components.forEach(c => showTree(c.component, level + 1, c.amount));
    }
 
}
 
for(let k in codesMap) {
    const thing = codesMap[k];
    if(thing.isComponent) continue;
 
    showTree(thing, 0); 
}