50 lines
1.4 KiB
JavaScript
50 lines
1.4 KiB
JavaScript
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import _curry2 from "./internal/_curry2.js";
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import _dispatchable from "./internal/_dispatchable.js";
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import _xtakeWhile from "./internal/_xtakeWhile.js";
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import slice from "./slice.js";
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/**
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* Returns a new list containing the first `n` elements of a given list,
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* passing each value to the supplied predicate function, and terminating when
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* the predicate function returns `false`. Excludes the element that caused the
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* predicate function to fail. The predicate function is passed one argument:
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* *(value)*.
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*
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* Dispatches to the `takeWhile` method of the second argument, if present.
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*
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* Acts as a transducer if a transformer is given in list position.
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*
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* @func
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* @memberOf R
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* @since v0.1.0
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* @category List
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* @sig (a -> Boolean) -> [a] -> [a]
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* @sig (a -> Boolean) -> String -> String
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* @param {Function} fn The function called per iteration.
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* @param {Array} xs The collection to iterate over.
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* @return {Array} A new array.
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* @see R.dropWhile, R.transduce, R.addIndex
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* @example
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*
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* const isNotFour = x => x !== 4;
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*
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* R.takeWhile(isNotFour, [1, 2, 3, 4, 3, 2, 1]); //=> [1, 2, 3]
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*
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* R.takeWhile(x => x !== 'd' , 'Ramda'); //=> 'Ram'
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*/
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var takeWhile =
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/*#__PURE__*/
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_curry2(
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/*#__PURE__*/
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_dispatchable(['takeWhile'], _xtakeWhile, function takeWhile(fn, xs) {
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var idx = 0;
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var len = xs.length;
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while (idx < len && fn(xs[idx])) {
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idx += 1;
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}
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return slice(0, idx, xs);
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}));
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export default takeWhile;
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