Function isSetter

packages/joint-react/src/utils/is.ts:10–13

(value: unknown)

export type Setter<Value> = (item: Value) => Value;

export function isSetter(value: unknown): value is Setter<unknown> {
  // check if value is a function and there is parameter
  return typeof value === 'function' && value.length === 1;
}

export function isDiaId(value: unknown): value is dia.Cell.ID {
  return util.isString(value) || util.isNumber(value);