createFlow.js
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var LodashWrapper = require('./LodashWrapper'),
getData = require('./getData'),
getFuncName = require('./getFuncName'),
isArray = require('../lang/isArray'),
isLaziable = require('./isLaziable');
/** Used as the `TypeError` message for "Functions" methods. */
var FUNC_ERROR_TEXT = 'Expected a function';
/**
* 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 function() {
var length = arguments.length;
if (!length) {
return function() { return arguments[0]; };
}
var wrapper,
index = fromRight ? length : -1,
leftIndex = 0,
funcs = Array(length);
while ((fromRight ? index-- : ++index < length)) {
var func = funcs[leftIndex++] = arguments[index];
if (typeof func != 'function') {
throw new TypeError(FUNC_ERROR_TEXT);
}
var funcName = wrapper ? '' : getFuncName(func);
wrapper = funcName == 'wrapper' ? new LodashWrapper([]) : wrapper;
}
index = wrapper ? -1 : length;
while (++index < length) {
func = funcs[index];
funcName = getFuncName(func);
var data = funcName == 'wrapper' ? getData(func) : null;
if (data && isLaziable(data[0])) {
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;
if (wrapper && args.length == 1 && isArray(args[0])) {
return wrapper.plant(args[0]).value();
}
var index = 0,
result = funcs[index].apply(this, args);
while (++index < length) {
result = funcs[index].call(this, result);
}
return result;
};
};
}
module.exports = createFlow;