extend.js

var assert = require('./assert');
var isFunction = require('./isFunction');
var isArray = require('./isArray');
var mixin = require('./mixin');
var isStruct = require('./isStruct');
var isInterface = require('./isInterface');
var isObject = require('./isObject');
var refinement = require('./refinement');
var decompose = require('./decompose');

function compose(predicates, unrefinedType, name) {
  var result = predicates.reduce(function (type, predicate) {
    return refinement(type, predicate);
  }, unrefinedType);
  if (name) {
    result.displayName = name;
    result.meta.name = name;
  }
  return result;
}

function getProps(type) {
  return isObject(type) ? type : type.meta.props;
}

function getDefaultProps(type) {
  return isObject(type) ? null : type.meta.defaultProps;
}

function pushAll(arr, elements) {
  Array.prototype.push.apply(arr, elements);
}

function extend(combinator, mixins, options) {
  if (process.env.NODE_ENV !== 'production') {
    assert(isFunction(combinator), function () { return 'Invalid argument combinator supplied to extend(combinator, mixins, options), expected a function'; });
    assert(isArray(mixins), function () { return 'Invalid argument mixins supplied to extend(combinator, mixins, options), expected an array'; });
  }
  var props = {};
  var prototype = {};
  var predicates = [];
  var defaultProps = {};
  mixins.forEach(function (x, i) {
    var decomposition = decompose(x);
    var unrefinedType = decomposition.unrefinedType;
    if (process.env.NODE_ENV !== 'production') {
      assert(isObject(unrefinedType) || isStruct(unrefinedType) || isInterface(unrefinedType), function () { return 'Invalid argument mixins[' + i + '] supplied to extend(combinator, mixins, options), expected an object, struct, interface or a refinement (of struct or interface)'; });
    }
    pushAll(predicates, decomposition.predicates);
    mixin(props, getProps(unrefinedType));
    mixin(prototype, unrefinedType.prototype);
    mixin(defaultProps, getDefaultProps(unrefinedType), true);
  });
  options = combinator.getOptions(options);
  options.defaultProps = mixin(defaultProps, options.defaultProps, true);
  var result = compose(predicates, combinator(props, {
    strict: options.strict,
    defaultProps: options.defaultProps
  }), options.name);
  mixin(result.prototype, prototype);
  return result;
}

module.exports = extend;