@atlaskit/theme/dist/cjs/utils/create-theme.js

Theme contains solutions for global theming, colors, and other useful mixins.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
var _typeof = require("@babel/runtime/helpers/typeof");
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createTheme = createTheme;
var _objectWithoutProperties2 = _interopRequireDefault(require("@babel/runtime/helpers/objectWithoutProperties"));
var _react = _interopRequireWildcard(require("react"));
var _excluded = ["children"];
function _interopRequireWildcard(e, t) { if ("function" == typeof WeakMap) var r = new WeakMap(), n = new WeakMap(); return (_interopRequireWildcard = function _interopRequireWildcard(e, t) { if (!t && e && e.__esModule) return e; var o, i, f = { __proto__: null, default: e }; if (null === e || "object" != _typeof(e) && "function" != typeof e) return f; if (o = t ? n : r) { if (o.has(e)) return o.get(e); o.set(e, f); } for (var _t in e) "default" !== _t && {}.hasOwnProperty.call(e, _t) && ((i = (o = Object.defineProperty) && Object.getOwnPropertyDescriptor(e, _t)) && (i.get || i.set) ? o(f, _t, i) : f[_t] = e[_t]); return f; })(e, t); }
/**
 * createTheme is used to create a set of Providers and Consumers for theming components.
 * - Takes a default theme function; this theme function gets a set of props, and returns tokens
 *  based on those props. An example of this default theme function is one that produces the standard
 *  appearance of the component
 * - Returns three things - a Provider that allow for additional themes to be applied, a Consumer
 *  that can get the current theme and fetch it, and a custom hook - useTheme which provides an alternate (although functionally the same) API
 *  to the Consumer.
 */
function createTheme(defaultGetTokens) {
  var emptyThemeFn = function emptyThemeFn(getTokens, props) {
    return getTokens(props);
  };

  /**
   * Internally, Theme uses React Context, with internal providers and consumers.
   * The React Context passes only a function that gets props, and turns them into tokens. This
   * function gets mixed as more Providers with their own themes are added. This mixed function
   * is ultimately picked up by Consumers, which implement a context consumer internally to fetch
   * the theme.
   */
  var ThemeContext = /*#__PURE__*/(0, _react.createContext)(defaultGetTokens);
  function useTheme(themeProps) {
    var theme = (0, _react.useContext)(ThemeContext);
    var themeFn = theme || emptyThemeFn;
    var tokens = themeFn(themeProps);
    return tokens;
  }

  // The Theme Consumer takes a function as its child - this function takes tokens, and the
  // return value is generally a set of nodes with the tokens applied appropriately.
  function Consumer(props) {
    var children = props.children,
      themeProps = (0, _objectWithoutProperties2.default)(props, _excluded);

    // @ts-ignore See issue for more info: https://github.com/Microsoft/TypeScript/issues/10727
    // Argument of type 'Pick<ThemeProps & { children: (tokens: ThemeTokens) => ReactNode; }, Exclude<keyof ThemeProps, "children">>' is not assignable to parameter of type 'ThemeProps'.ts(2345)
    var tokens = useTheme(themeProps);
    // We add a fragment to ensure we don't break people upgrading.
    // Previously they may have been able to pass in undefined without things blowing up.
    return /*#__PURE__*/_react.default.createElement(_react.default.Fragment, null, children(tokens));
  }

  /**
   * The Theme Provider takes regular nodes as its children, but also takes a *theme function*
   * - The theme function takes a set of props, as well as a function (getTokens) that can turn props into tokens.
   * - The getTokens function isn't called immediately - instead the props are passed
   *    through a mix of parent theming functions
   * Children of this provider will receive this mixed theme
   */
  function Provider(props) {
    var themeFn = (0, _react.useContext)(ThemeContext);
    var valueFn = props.value || emptyThemeFn;
    var mixedFn = (0, _react.useCallback)(function (themeProps) {
      return valueFn(themeFn, themeProps);
    }, [themeFn, valueFn]);
    return /*#__PURE__*/_react.default.createElement(ThemeContext.Provider, {
      value: mixedFn
    }, props.children);
  }
  return {
    Consumer: Consumer,
    Provider: Provider,
    useTheme: useTheme
  };
}