saleor-dashboard/src/storybook/mock.tsx

import React from "react";

interface ChoiceProviderProps {
  children: (props: {
    choices: Array<{
      label: string;
      value: string;
    }>;
    loading: boolean;
    fetchChoices(value: string);
  }) => React.ReactElement<any>;
  choices: Array<{
    label: string;
    value: string;
  }>;
}
interface ChoiceProviderState {
  choices: Array<{
    label: string;
    value: string;
  }>;
  loading: boolean;
  timeout: any;
}

export class ChoiceProvider extends React.Component<
  ChoiceProviderProps,
  ChoiceProviderState
> {
  state = { choices: [], loading: false, timeout: null };

  handleChange = (inputValue: string) => {
    if (this.state.loading) {
      clearTimeout(this.state.timeout);
    }
    const timeout = setTimeout(() => this.fetchChoices(inputValue), 500);
    this.setState({
      loading: true,
      timeout
    });
  };

  fetchChoices = (inputValue: string) => {
    this.setState({
      choices: this.props.choices
        .filter(
          suggestion =>
            !inputValue ||
            suggestion.label.toLowerCase().indexOf(inputValue.toLowerCase()) !==
              -1
        )
        .slice(0, 10),
      loading: false,
      timeout: null
    });
  };

  render() {
    return this.props.children({
      choices: this.state.choices,
      fetchChoices: this.handleChange,
      loading: this.state.loading
    });
  }
}