var baseCallback = require('../internal/baseCallback'), baseWhile = require('../internal/baseWhile'); /** * Creates a slice of `array` with elements taken from the beginning. Elements * are taken until `predicate` returns falsey. The predicate is bound to * `thisArg` and invoked with three arguments: (value, index, array). * * If a property name is provided for `predicate` the created `_.property` * style callback returns the property value of the given element. * * If a value is also provided for `thisArg` the created `_.matchesProperty` * style callback returns `true` for elements that have a matching property * value, else `false`. * * If an object is provided for `predicate` the created `_.matches` style * callback returns `true` for elements that have the properties of the given * object, else `false`. * * @static * @memberOf _ * @category Array * @param {Array} array The array to query. * @param {Function|Object|string} [predicate=_.identity] The function invoked * per iteration. * @param {*} [thisArg] The `this` binding of `predicate`. * @returns {Array} Returns the slice of `array`. * @example * * _.takeWhile([1, 2, 3], function(n) { * return n < 3; * }); * // => [1, 2] * * var users = [ * { 'user': 'barney', 'active': false }, * { 'user': 'fred', 'active': false}, * { 'user': 'pebbles', 'active': true } * ]; * * // using the `_.matches` callback shorthand * _.pluck(_.takeWhile(users, { 'user': 'barney', 'active': false }), 'user'); * // => ['barney'] * * // using the `_.matchesProperty` callback shorthand * _.pluck(_.takeWhile(users, 'active', false), 'user'); * // => ['barney', 'fred'] * * // using the `_.property` callback shorthand * _.pluck(_.takeWhile(users, 'active'), 'user'); * // => [] */ function takeWhile(array, predicate, thisArg) { return (array && array.length) ? baseWhile(array, baseCallback(predicate, thisArg, 3)) : []; } module.exports = takeWhile;