SOURCE

var tree2 = {
    name: "page.js",
    require: [
        {
            name: "A.js",
            require: [
                {
                    name: "B.js",
                    require: [
                        {
                            name: "C.js",
                            require: [
                                {
                                    name: "E.js"
                                }
                            ]
                        },
                    ],
                },
            ],
        },
        {
            name: "D.js",
            require: [
                {
                    name: "C.js",
                    require: [
                        {
                            name: "E.js"
                        }
                    ]
                },
                {
                    name: "E.js",
                },
            ],
        }
    ],
};

function resolve(node) {
    const totalDeps = [];
    const { name, require = [] } = node;

    if (require.length === 0) {
        return [name];
    }

    for (const requireNode of require) {
        let deps = resolve(requireNode);
        deps = deps.filter(dep => !totalDeps.includes(dep));
        totalDeps.push(...deps);
    }
    totalDeps.push(name);

    return totalDeps;
}

console.log(resolve(tree2));