| var LodashWrapper = require('./_LodashWrapper'), | |
|     flatRest = require('./_flatRest'), | |
|     getData = require('./_getData'), | |
|     getFuncName = require('./_getFuncName'), | |
|     isArray = require('./isArray'), | |
|     isLaziable = require('./_isLaziable'); | |
| 
 | |
| /** Error message constants. */ | |
| var FUNC_ERROR_TEXT = 'Expected a function'; | |
| 
 | |
| /** Used to compose bitmasks for function metadata. */ | |
| var WRAP_CURRY_FLAG = 8, | |
|     WRAP_PARTIAL_FLAG = 32, | |
|     WRAP_ARY_FLAG = 128, | |
|     WRAP_REARG_FLAG = 256; | |
| 
 | |
| /** | |
|  * Creates a `_.flow` or `_.flowRight` function. | |
|  * | |
|  * @private | |
|  * @param {boolean} [fromRight] Specify iterating from right to left. | |
|  * @returns {Function} Returns the new flow function. | |
|  */ | |
| function createFlow(fromRight) { | |
|   return flatRest(function(funcs) { | |
|     var length = funcs.length, | |
|         index = length, | |
|         prereq = LodashWrapper.prototype.thru; | |
| 
 | |
|     if (fromRight) { | |
|       funcs.reverse(); | |
|     } | |
|     while (index--) { | |
|       var func = funcs[index]; | |
|       if (typeof func != 'function') { | |
|         throw new TypeError(FUNC_ERROR_TEXT); | |
|       } | |
|       if (prereq && !wrapper && getFuncName(func) == 'wrapper') { | |
|         var wrapper = new LodashWrapper([], true); | |
|       } | |
|     } | |
|     index = wrapper ? index : length; | |
|     while (++index < length) { | |
|       func = funcs[index]; | |
| 
 | |
|       var funcName = getFuncName(func), | |
|           data = funcName == 'wrapper' ? getData(func) : undefined; | |
| 
 | |
|       if (data && isLaziable(data[0]) && | |
|             data[1] == (WRAP_ARY_FLAG | WRAP_CURRY_FLAG | WRAP_PARTIAL_FLAG | WRAP_REARG_FLAG) && | |
|             !data[4].length && data[9] == 1 | |
|           ) { | |
|         wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]); | |
|       } else { | |
|         wrapper = (func.length == 1 && isLaziable(func)) | |
|           ? wrapper[funcName]() | |
|           : wrapper.thru(func); | |
|       } | |
|     } | |
|     return function() { | |
|       var args = arguments, | |
|           value = args[0]; | |
| 
 | |
|       if (wrapper && args.length == 1 && isArray(value)) { | |
|         return wrapper.plant(value).value(); | |
|       } | |
|       var index = 0, | |
|           result = length ? funcs[index].apply(this, args) : value; | |
| 
 | |
|       while (++index < length) { | |
|         result = funcs[index].call(this, result); | |
|       } | |
|       return result; | |
|     }; | |
|   }); | |
| } | |
| 
 | |
| module.exports = createFlow;
 |