deep_merge.js

  updateFormData(object) {
    //initial state of address container
    //addressContainer: {
    //  #1RegisteredAddress: {
    //    line_2: '2',
    //    line_3, '3'
    //  }
    //  #2DividendAddres: {
    //    Line2: "2",
    //    Line3: "3"
    //   }
    //}
    //we expect an object with a single key and value
    const firstKey = (anyObject) => R.keys(anyObject)[0];
    const rootObjectKey = firstKey(object); //#1RegisteredAddress
    const rootObjectValue = object[rootObjectKey]; //{Line_1: 1}
    //we also expect the nestedObject to have a single key and value
    const nestedObjectKey = firstKey(rootObjectValue); //Line_1
    const nestedObjectValue = R.prop(nestedObjectKey, rootObjectValue); //1
    const updateNestedProp =
     (acc, next) => R.assocPath([rootObjectKey, nestedObjectKey], nestedObjectValue, next);
    const updatedState =
      R.reduce(updateNestedProp, {}, [this.state.addressContainer]);
      
    //final state of address container
    //addressContainer: {
    //  #1RegisteredAddress: {
    //    Line_1: "1",
    //    line_2: '2',
    //    line_3, '3'
    //  }
    //  #2DividendAddres: {
    //    Line2: "2",
    //    Line3: "3"
    //   }
    //}
    this.setState({addressContainer: updatedState});
  }