1 | import _arity from "./internal/_arity.js";
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2 | import _curry1 from "./internal/_curry1.js";
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3 | import map from "./map.js";
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4 | import max from "./max.js";
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5 | import reduce from "./reduce.js";
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6 | /**
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7 | * Returns a function, `fn`, which encapsulates `if/else, if/else, ...` logic.
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8 | * `R.cond` takes a list of [predicate, transformer] pairs. All of the arguments
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9 | * to `fn` are applied to each of the predicates in turn until one returns a
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10 | * "truthy" value, at which point `fn` returns the result of applying its
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11 | * arguments to the corresponding transformer. If none of the predicates
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12 | * matches, `fn` returns undefined.
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13 | *
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14 | * @func
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15 | * @memberOf R
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16 | * @since v0.6.0
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17 | * @category Logic
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18 | * @sig [[(*... -> Boolean),(*... -> *)]] -> (*... -> *)
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19 | * @param {Array} pairs A list of [predicate, transformer]
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20 | * @return {Function}
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21 | * @see R.ifElse, R.unless, R.when
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22 | * @example
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23 | *
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24 | * const fn = R.cond([
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25 | * [R.equals(0), R.always('water freezes at 0°C')],
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26 | * [R.equals(100), R.always('water boils at 100°C')],
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27 | * [R.T, temp => 'nothing special happens at ' + temp + '°C']
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28 | * ]);
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29 | * fn(0); //=> 'water freezes at 0°C'
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30 | * fn(50); //=> 'nothing special happens at 50°C'
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31 | * fn(100); //=> 'water boils at 100°C'
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32 | */
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33 |
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34 | var cond =
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35 | /*#__PURE__*/
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36 | _curry1(function cond(pairs) {
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37 | var arity = reduce(max, 0, map(function (pair) {
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38 | return pair[0].length;
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39 | }, pairs));
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40 | return _arity(arity, function () {
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41 | var idx = 0;
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42 |
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43 | while (idx < pairs.length) {
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44 | if (pairs[idx][0].apply(this, arguments)) {
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45 | return pairs[idx][1].apply(this, arguments);
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46 | }
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47 |
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48 | idx += 1;
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49 | }
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50 | });
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51 | });
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52 |
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53 | export default cond; |
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