How to add a custom field to a form

Overview

In addition to the standard form fields, you can create your own custom fields using controls from the Element UI library. Here's an example of how to create a field with DatePicker control and age validation.

In this guide, we will be working with a clone of our public GitHub repository. We strongly recommend that you read the guide on how to build Workflow Server from this repository.

Adding custom control

1. Open or create the Form.

2. In the Fields section, add a new field with the following parameters: Name: "BirthDate", Title: "Birth date", Control: "custom".

3. Replace the span tag with el-date-picker.

4. Add the attribute :rules="[WorkflowServer.Rules.age]" to the el-form-item, it will ensure that custom validation is called.

   Here is an example of code:

   <div wfs-content="fields">
   	<el-form-item name="BirthDate" prop="BirthDate" label="Birth Date"
   	              :rules="[WorkflowServer.Rules.age]">
   		<el-date-picker v-model="FormData.BirthDate" :readonly="isreadonly()">
   		</el-date-picker>
   	</el-form-item>
   </div>

5. To add the validation function, open the WorkflowServer.js file.

6. In the Rules field of the WorkflowServer object, create a new validator:

   Here is an example of code:

   Before the WorkflowServer object

   function isAgeValid(value) {
     if (!value) return true;
     const date = new Date(value);
     const now = new Date();
     if (now < date) return false;
     const age = new Date(now - date);
     return Math.abs(age.getUTCFullYear() - 1970);
   }
   Inside the WorkflowServer object

    age: {
      required: true,
      validator: (rule, value, callback) => {
        if (isAgeValid(value)) {
          callback()
        } else {
          callback(new Error(rule.message))
        }
      },
      message: 'You\'re too young'
    }

7. Rebuild the frontend. See this guide for more information.

8. After attaching the form to the process, you can see the result: