wilderness-core/modules/middleware.js

The SVG animation engine behind Wilderness

var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; };

/**
 * A group of functions to transform/untransform a value.
 *
 * @typedef {Object} Middleware
 *
 * @property {string} name - The name of the middleware.
 * @property {function} input - Transform.
 * @property {function} output - Untransform.
 */

/**
 * Run every part of a value through a function.
 *
 * @param {*} value
 * @param {function} func
 *
 * @returns {*}
 *
 * @example
 * apply(2, n => n * 2)
 */
var apply = function apply(value, func) {
  var v = func(value);

  if ((typeof v === 'undefined' ? 'undefined' : _typeof(v)) !== 'object') {
    return v;
  } else if (Array.isArray(v)) {
    var arr = [];

    for (var i = 0, l = v.length; i < l; i++) {
      arr.push(apply(v[i], func));
    }

    return arr;
  } else if (v !== null) {
    var obj = {};

    for (var k in v) {
      obj[k] = apply(v[k], func);
    }

    return obj;
  }

  return v;
};

/**
 * Runs each Middleware input function in turn on a value.
 *
 * @param {*} value
 * @param {Middleware[]} middleware
 *
 * @returns {*}
 *
 * @example
 * input({ foo: 1, bar: [ 2, 3 ] }, middleware)
 */
var input = function input(value, middleware) {
  var v = value;

  for (var i = 0, l = middleware.length; i < l; i++) {
    v = apply(v, middleware[i].input);
  }

  return v;
};

/**
 * Runs each Middleware output function in reverse on a value.
 *
 * @param {*} value
 * @param {Middleware[]} middleware
 *
 * @returns {*}
 *
 * @example
 * output({ foo: 1, bar: [ 2, 3 ] }, middleware)
 */
var output = function output(value, middleware) {
  var v = value;

  for (var i = middleware.length - 1; i >= 0; i--) {
    v = apply(v, middleware[i].output);
  }

  return v;
};

export { input, output };