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

  fetchChoices = inputValue => {
    let count = 0;
    this.setState({
      choices: this.props.choices.filter(suggestion => {
        const keep =
          (!inputValue ||
            suggestion.label.toLowerCase().indexOf(inputValue.toLowerCase()) !==
              -1) &&
          count < 5;

        if (keep) {
          count += 1;
        }

        return keep;
      }),
      loading: false,
      timeout: null
    });
  };

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