ramda/src/takeWhile.js

var _curry2 =
/*#__PURE__*/
require("./internal/_curry2");

var _dispatchable =
/*#__PURE__*/
require("./internal/_dispatchable");

var _xtakeWhile =
/*#__PURE__*/
require("./internal/_xtakeWhile");

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


var takeWhile =
/*#__PURE__*/
_curry2(
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_dispatchable(['takeWhile'], _xtakeWhile, function takeWhile(fn, xs) {
  var idx = 0;
  var len = xs.length;

  while (idx < len && fn(xs[idx])) {
    idx += 1;
  }

  return slice(0, idx, xs);
}));

module.exports = takeWhile;