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;