fluo/src/mixer.js

A prototype-based fork of the Reflux data flow library similar to Facebook Flux

var _ = require('./utils');

module.exports = function mix(def) {
    var composed = {
        init: [],
        preEmit: [],
        shouldEmit: []
    };

    var updated = (function mixDef(mixin) {
        var mixed = {};
        if (mixin.mixins) {
            mixin.mixins.forEach(function (subMixin) {
                _.extend(mixed, mixDef(subMixin));
            });
        }
        _.extend(mixed, mixin);
        Object.keys(composed).forEach(function (composable) {
            if (mixin.hasOwnProperty(composable)) {
                composed[composable].push(mixin[composable]);
            }
        });
        return mixed;
    }(def));

    if (composed.init.length > 1) {
        updated.init = function () {
            var args = arguments;
            composed.init.forEach(function (init) {
                init.apply(this, args);
            }, this);
        };
    }
    if (composed.preEmit.length > 1) {
        updated.preEmit = function () {
            return composed.preEmit.reduce(function (args, preEmit) {
                var newValue = preEmit.apply(this, args);
                return newValue === undefined ? args : [newValue];
            }.bind(this), arguments);
        };
    }
    if (composed.shouldEmit.length > 1) {
        updated.shouldEmit = function () {
            var args = arguments;
            return !composed.shouldEmit.some(function (shouldEmit) {
                return !shouldEmit.apply(this, args);
            }, this);
        };
    }
    Object.keys(composed).forEach(function (composable) {
        if (composed[composable].length === 1) {
            updated[composable] = composed[composable][0];
        }
    });

    return updated;
};