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- 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;
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