Code coverage report for lib/util/composeReducer.js

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/**
 * @file 合成reducer
 * @author Leon(leon@outlook.com)
 * @requires underscore
 */
 
var u = require('underscore');
 
/**
 * 合成reducer
 *
 * @public
 * @method module:ei.composeReducer
 * @param {...(Function | Object)} reducers 一个reducer，或多个reducer的map
 * @return {Function}
 */
function composeReducer(reducers) {
 
    if (u.isFunction(reducers)) {
        return reducers;
    }
 
    reducers = u.reduce(
        u.toArray(arguments),
        function (finalReducer, reducer) {
            return u.extendOwn(finalReducer, reducer);
        },
        {}
    );
 
    return function (state, action) {
 
        var isChanged = false;
        var nextState = {};
 
 
        for (var name in state) {
 
            if (!u.has(state, name)) {
                continue;
            }
 
            if (u.has(reducers, name)) {
 
                var value = state[name];
                var nextValue = nextState[name] = reducers[name](value, action);
 
                if (nextValue !== value) {
                    isChanged = true;
                }
 
            }
            else {
                nextState[name] = state[name];
            }
 
 
        }
 
        return isChanged ? nextState : state;
 
    };
 
}
 
module.exports = composeReducer;