1 | var _reduce =
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2 | /*#__PURE__*/
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3 | require("./internal/_reduce");
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4 |
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5 | var _xwrap =
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6 | /*#__PURE__*/
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7 | require("./internal/_xwrap");
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8 |
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9 | var curryN =
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10 | /*#__PURE__*/
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11 | require("./curryN");
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12 | /**
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13 | * Initializes a transducer using supplied iterator function. Returns a single
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14 | * item by iterating through the list, successively calling the transformed
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15 | * iterator function and passing it an accumulator value and the current value
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16 | * from the array, and then passing the result to the next call.
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17 | *
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18 | * The iterator function receives two values: *(acc, value)*. It will be
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19 | * wrapped as a transformer to initialize the transducer. A transformer can be
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20 | * passed directly in place of an iterator function. In both cases, iteration
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21 | * may be stopped early with the [`R.reduced`](#reduced) function.
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22 | *
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23 | * A transducer is a function that accepts a transformer and returns a
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24 | * transformer and can be composed directly.
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25 | *
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26 | * A transformer is an an object that provides a 2-arity reducing iterator
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27 | * function, step, 0-arity initial value function, init, and 1-arity result
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28 | * extraction function, result. The step function is used as the iterator
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29 | * function in reduce. The result function is used to convert the final
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30 | * accumulator into the return type and in most cases is
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31 | * [`R.identity`](#identity). The init function can be used to provide an
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32 | * initial accumulator, but is ignored by transduce.
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33 | *
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34 | * The iteration is performed with [`R.reduce`](#reduce) after initializing the transducer.
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35 | *
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36 | * @func
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37 | * @memberOf R
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38 | * @since v0.12.0
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39 | * @category List
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40 | * @sig (c -> c) -> ((a, b) -> a) -> a -> [b] -> a
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41 | * @param {Function} xf The transducer function. Receives a transformer and returns a transformer.
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42 | * @param {Function} fn The iterator function. Receives two values, the accumulator and the
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43 | * current element from the array. Wrapped as transformer, if necessary, and used to
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44 | * initialize the transducer
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45 | * @param {*} acc The initial accumulator value.
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46 | * @param {Array} list The list to iterate over.
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47 | * @return {*} The final, accumulated value.
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48 | * @see R.reduce, R.reduced, R.into
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49 | * @example
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50 | *
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51 | * const numbers = [1, 2, 3, 4];
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52 | * const transducer = R.compose(R.map(R.add(1)), R.take(2));
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53 | * R.transduce(transducer, R.flip(R.append), [], numbers); //=> [2, 3]
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54 | *
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55 | * const isOdd = (x) => x % 2 === 1;
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56 | * const firstOddTransducer = R.compose(R.filter(isOdd), R.take(1));
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57 | * R.transduce(firstOddTransducer, R.flip(R.append), [], R.range(0, 100)); //=> [1]
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58 | */
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59 |
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60 |
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61 | var transduce =
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62 | /*#__PURE__*/
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63 | curryN(4, function transduce(xf, fn, acc, list) {
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64 | return _reduce(xf(typeof fn === 'function' ? _xwrap(fn) : fn), acc, list);
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65 | });
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66 | module.exports = transduce; |
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