freeCodeCamp/arguments-optional.english.md at 28575e987771914169c6e2e473a10bfc7c52c353

Randell Dawson 3ec1fe8ea7 feat: add forumTopicId to challenge frontmatter [pre-existing]

This commit adds the pre-existing challenge guide topics in the
forum to the forntmatter of their challenge markdown files.

2019-08-05 22:14:37 +05:30

2.2 KiB

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id, title, isRequired, challengeType, forumTopicId

id	title	isRequired	challengeType	forumTopicId
a97fd23d9b809dac9921074f	Arguments Optional	true	5	14271

Description

Create a function that sums two arguments together. If only one argument is provided, then return a function that expects one argument and returns the sum. For example, addTogether(2, 3) should return 5, and addTogether(2) should return a function. Calling this returned function with a single argument will then return the sum: var sumTwoAnd = addTogether(2); sumTwoAnd(3) returns 5. If either argument isn't a valid number, return undefined. Remember to use Read-Search-Ask if you get stuck. Try to pair program. Write your own code.

Instructions

Tests

tests:
  - text: <code>addTogether(2, 3)</code> should return 5.
    testString: assert.deepEqual(addTogether(2, 3), 5);
  - text: <code>addTogether(2)(3)</code> should return 5.
    testString: assert.deepEqual(addTogether(2)(3), 5);
  - text: <code>addTogether("http://bit.ly/IqT6zt")</code> should return undefined.
    testString: assert.isUndefined(addTogether("http://bit.ly/IqT6zt"));
  - text: <code>addTogether(2, "3")</code> should return undefined.
    testString: assert.isUndefined(addTogether(2, "3"));
  - text: <code>addTogether(2)([3])</code> should return undefined.
    testString: assert.isUndefined(addTogether(2)([3]));

Challenge Seed

function addTogether() {
  return false;
}

addTogether(2,3);

Solution

function addTogether() {
  var a = arguments[0];
  if (toString.call(a) !== '[object Number]') return;
  if (arguments.length === 1) {
    return function(b) {
      if (toString.call(b) !== '[object Number]') return;
      return a + b;
    };
  }
  var b = arguments[1];
  if (toString.call(b) !== '[object Number]') return;
  return a + arguments[1];
}

2.2 KiB Raw Blame History