set

set.js

// assuming keypath is string | number array like `['foo', 0, 'bar']`
export function set(object, keypath, value) {
  if (keypath.length === 0) {
    return value;
  }

  const segments = keypath.slice(0, -1);
  const finalSegment = keypath.slice(-1)[0];

  const leaf = segments.reduce((node, key) => {
    if (node[key]) {
      return node[key];
    }
    node[key] = {};
    return node[key];
  }, object);

  leaf[finalSegment] = value;
  return object;
}