React.js senior developer to migrate and refactor existing PHP development

We are looking for a senior react developer, with availability in the long term, to help us migrate a complex application developed in PHP to react. We are also considering the use of a template engine such as Mustache or similar. This task is just a first small project that will be followed for many other tasks. We plan to assign this first task to more than one freelancer. Then we will continue working with the developer that has done a better job. For this first basic development, we would like to have created a small console to generate a JSON file based on the elements in a tree. Check the attached screenshot for reference. This shows the actual interface of our PHP console. We would like the new one to look similar to it, but open to any improvement. The console should have three columns: - the first, where we will be able to create several trees as the one shown in the screenshot. We are currently using an accordion object to display all the available trees in the same column. - the second column, where we'll have a form to configure several attributes of the selected node in the tree of the first column - the third column, where we'll have another tree of available elements, to map with the selected element in the first map. After generating one of the trees in the left, and filling its attributes and mapping the elements with the ones in the right tree, we want to export the left tree to a JSON file, such as this: "id": "tree name", "text": "Name", "icon": "icon", "mapID": "1", "primary": [{ "id": "First element", "text": "First element", "icon": "icon1", "children": [{ "id": "children1", "text": "First child of first element", "icon": "icon2", "levels": [{ "id": "children1-1", "text": "Acme", "icon": "icon2", "data": "[login to view URL]" }, { "id": "children1-2", "text": "Not Acme", "icon": "icon2", "data": "[login to view URL]" }] }, ... We will provide a full JSON file for reference to the selected freelancers. The use of clean code, best practices, test-driven development is welcome. Any suggestion is welcome.