freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/drop-it.english.md

id	title	isRequired	challengeType
a5deed1811a43193f9f1c841	Drop it	true	5

Description

Given the array arr, iterate through and remove each element starting from the first element (the 0 index) until the function func returns true when the iterated element is passed through it. Then return the rest of the array once the condition is satisfied, otherwise, arr should be returned as an empty array. Remember to use Read-Search-Ask if you get stuck. Try to pair program. Write your own code.

Instructions

Tests

tests:
  - text: <code>dropElements([1, 2, 3, 4], function(n) {return n >= 3;})</code> should return <code>[3, 4]</code>.
    testString: assert.deepEqual(dropElements([1, 2, 3, 4], function(n) {return n >= 3;}), [3, 4], '<code>dropElements([1, 2, 3, 4], function(n) {return n >= 3;})</code> should return <code>[3, 4]</code>.');
  - text: <code>dropElements([0, 1, 0, 1], function(n) {return n === 1;})</code> should return <code>[1, 0, 1]</code>.
    testString: assert.deepEqual(dropElements([0, 1, 0, 1], function(n) {return n === 1;}), [1, 0, 1], '<code>dropElements([0, 1, 0, 1], function(n) {return n === 1;})</code> should return <code>[1, 0, 1]</code>.');
  - text: <code>dropElements([1, 2, 3], function(n) {return n > 0;})</code> should return <code>[1, 2, 3]</code>.
    testString: assert.deepEqual(dropElements([1, 2, 3], function(n) {return n > 0;}), [1, 2, 3], '<code>dropElements([1, 2, 3], function(n) {return n > 0;})</code> should return <code>[1, 2, 3]</code>.');
  - text: <code>dropElements([1, 2, 3, 4], function(n) {return n > 5;})</code> should return <code>[]</code>.
    testString: assert.deepEqual(dropElements([1, 2, 3, 4], function(n) {return n > 5;}), [], '<code>dropElements([1, 2, 3, 4], function(n) {return n > 5;})</code> should return <code>[]</code>.');
  - text: <code>dropElements([1, 2, 3, 7, 4], function(n) {return n > 3;})</code> should return <code>[7, 4]</code>.
    testString: assert.deepEqual(dropElements([1, 2, 3, 7, 4], function(n) {return n > 3;}), [7, 4], '<code>dropElements([1, 2, 3, 7, 4], function(n) {return n > 3;})</code> should return <code>[7, 4]</code>.');
  - text: <code>dropElements([1, 2, 3, 9, 2], function(n) {return n > 2;})</code> should return <code>[3, 9, 2]</code>.
    testString: assert.deepEqual(dropElements([1, 2, 3, 9, 2], function(n) {return n > 2;}), [3, 9, 2], '<code>dropElements([1, 2, 3, 9, 2], function(n) {return n > 2;})</code> should return <code>[3, 9, 2]</code>.');

Challenge Seed

function dropElements(arr, func) {
  // Drop them elements.
  return arr;
}

dropElements([1, 2, 3], function(n) {return n < 3; });

Solution

function dropElements(arr, func) {
  // Drop them elements.
  while (arr.length && !func(arr[0])) {
    arr.shift();
  }
  return arr;
}