Implement a Star Rating Custom Form Element using a Third Party Library

Implementing a custom form element allows you to augment the existing form elements that come with VertiGIS Studio Workflow.

This article will walk you through creating a form element that uses the react-star-ratings component to allow the user to select up to five stars.

Prerequisites

Follow the instructions in the Web Applications SDK page to set up your development environment.

note

A working knowledge of TypeScript is recommended before extending Workflow for web-based hosts.

Overview

Implementing a star rating custom form element for web applications using a third party library consists of the following steps:

1. Adding third party library dependencies to your project.
2. Creating the custom form element.
3. Implementing the custom form element using the third party library.

Adding Dependencies

1. Run npm install react-star-ratings in the terminal to install the third party react-star-ratings component.

Set up Custom Form Element Skeleton

To create a new form element:

1. Open the Workflow activity SDK in Visual Studio Code.
2. Run npm run generate in the terminal.
3. When prompted, select Form Element.
4. Enter the name of the form element you would like to create and press Enter. For example, StarRating.
5. Open the newly created src/elements/StarRating.tsx file.

Implement the Custom Form Element

Modify the skeleton form element implementation in src/elements/StarRating.tsx to match the following example.

src/elements/StarRating.tsx

import * as React from "react";
import StarRatings from "react-star-ratings";
import {
    FormElementProps,
    FormElementRegistration,
} from "@vertigis/workflow";

interface StarRatingProps extends FormElementProps<number> {}

/**
 * A simple React Component that displays a star rating input.
 * @param props The props that will be provided by the Workflow runtime.
 */
function StarRating(props: StarRatingProps): React.ReactElement {
    const { setValue, value } = props;

    // Update the form state when the rating value changes.
    const handleRatingChange = (newRating: number) => {
        setValue(newRating);
    };

    return (
        <StarRatings
            changeRating={handleRatingChange}
            rating={value}
            starDimension="1.5em"
            starHoverColor="#ffb400"
            starRatedColor="#ffb400"
        />
    );
}

const StarRatingElementRegistration: FormElementRegistration<StarRatingProps> =
    {
        component: StarRating,
        getInitialProperties: () => ({ value: 0 }),
        id: "StarRating",
    };

export default StarRatingElementRegistration;

Deploy the Form Element

Follow the instructions to build and deploy the activity pack.

Test the Form Element

Once your activity pack is hosted and registered, your StarRating custom form element should appear in the form element toolbox in VertiGIS Studio Workflow Designer alongside the built-in form elements.

To use your custom form element in a workflow:

1. Select the Display Form activity that you want to include your form element in.
2. Locate the StarRating form element in the toolbox and drag it onto the form.
3. Alternatively:
   1. Add a Custom form element to the form.
   2. Set the Custom Type property of the Custom form element to StarRating.
4. Test your workflow.