Flow

When codeTypeHandler extracts Flow props, the type information is written to flowType.


interface PropDescriptor {
  flowType?: TypeDescriptor<FunctionSignatureType>;
  required?: boolean;
  description?: string;
  defaultValue?: DefaultValueDescriptor;
}

Example

component.js


type Props = {
  label: string,
  disabled?: boolean,
  size: 'small' | 'large',
};
 
export function Button(props: Props) {
  return <button>{props.label}</button>;
}

JSON


{
  "label": {
    "required": true,
    "flowType": {
      "name": "string"
    }
  },
  "disabled": {
    "required": false,
    "flowType": {
      "name": "boolean"
    }
  },
  "size": {
    "required": true,
    "flowType": {
      "name": "union",
      "raw": "'small' | 'large'",
      "elements": [
        { "name": "literal", "value": "'small'" },
        { "name": "literal", "value": "'large'" }
      ]
    }
  }
}

Type descriptors

Most Flow values are represented with the shared TypeDescriptor<FunctionSignatureType> shape. Common descriptors are:

Simple descriptors, such as { "name": "string" }
Literal descriptors, such as { "name": "literal", "value": "'small'" }
Element descriptors, such as unions, intersections, arrays, and tuples
Function signatures with type: "function"
Object signatures with type: "object"

Files that are not parsed as TypeScript use Flow syntax by default unless a Babel configuration changes the parser plugins.