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