freeCodeCamp/write-arrow-functions-with-parameters.english.md at 23a3287d8f72990134445c592743eef426614f41

gaspersic/freeCodeCamp

Fork 0

Files

.github

api-server

client

config

curriculum

challenges

_meta

arabic

chinese

english

01-responsive-web-design

02-javascript-algorithms-and-data-structures

basic-algorithm-scripting

basic-data-structures

basic-javascript

debugging

es6

compare-scopes-of-the-var-and-let-keywords.english.md

complete-a-promise-with-resolve-and-reject.english.md

create-a-javascript-promise.english.md

create-a-module-script.english.md

create-an-export-fallback-with-export-default.english.md

create-strings-using-template-literals.english.md

declare-a-read-only-variable-with-the-const-keyword.english.md

explore-differences-between-the-var-and-let-keywords.english.md

handle-a-fulfilled-promise-with-then.english.md

handle-a-rejected-promise-with-catch.english.md

import-a-default-export.english.md

mutate-an-array-declared-with-const.english.md

prevent-object-mutation.english.md

reuse-javascript-code-using-import.english.md

set-default-parameters-for-your-functions.english.md

use--to-import-everything-from-a-file.english.md

use-arrow-functions-to-write-concise-anonymous-functions.english.md

use-class-syntax-to-define-a-constructor-function.english.md

use-destructuring-assignment-to-assign-variables-from-arrays.english.md

use-destructuring-assignment-to-assign-variables-from-nested-objects.english.md

use-destructuring-assignment-to-assign-variables-from-objects.english.md

use-destructuring-assignment-to-extract-values-from-objects.english.md

use-destructuring-assignment-to-pass-an-object-as-a-functions-parameters.english.md

use-destructuring-assignment-with-the-rest-parameter-to-reassign-array-elements.english.md

use-export-to-share-a-code-block.english.md

use-getters-and-setters-to-control-access-to-an-object.english.md

use-the-rest-parameter-with-function-parameters.english.md

use-the-spread-operator-to-evaluate-arrays-in-place.english.md

write-arrow-functions-with-parameters.english.md

write-concise-declarative-functions-with-es6.english.md

write-concise-object-literal-declarations-using-object-property-shorthand.english.md

functional-programming

intermediate-algorithm-scripting

javascript-algorithms-and-data-structures-projects

object-oriented-programming

regular-expressions

03-front-end-libraries

04-data-visualization

05-apis-and-microservices

06-information-security-and-quality-assurance

08-coding-interview-prep

09-certificates

portuguese

russian

spanish

formattingConversion

math-challenges

requiresTests

schema

test

.babelrc

.editorconfig

.npmignore

.travis.yml

CHANGELOG.md

LICENSE.md

commitizen.config.js

commitlint.config.js

create-challenge-bundle.js

getChallenges.js

gulpfile.js

index.js

lib.js

md-translation.js

package-entry.js

package-lock.json

package.json

utils.js

docs

search-indexing

tools

utils

.editorconfig

.eslintignore

.eslintrc.json

.gitattributes

.gitignore

.gitpod.yml

.node-inspectorrc

.prettierignore

.prettierrc

.snyk

.travis.yml

.vcmrc

CODE_OF_CONDUCT.md

CONTRIBUTING.md

Dockerfile.tests

LICENSE.md

README.md

SECURITY.md

change_volumes_owner.sh

docker-compose-shared.yml

docker-compose.tests.yml

docker-compose.yml

lerna.json

libcimp_index_js.patch

package-lock.json

package.json

patch_npm_and_install.sh

sample.env

Randell Dawson 568f00e02a fix(curriculum): Added forumTopicId to remaining 1200 challeng… (#36558 )

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

2.1 KiB

Raw Blame History

id, title, challengeType, forumTopicId

id	title	challengeType	forumTopicId
587d7b88367417b2b2512b44	Write Arrow Functions with Parameters	1	301223

Description

Just like a regular function, you can pass arguments into an arrow function.

// doubles input value and returns it
const doubler = (item) => item * 2;

If an arrow function has a single argument, the parentheses enclosing the argument may be omitted.

// the same function, without the argument parentheses
const doubler = item => item * 2;

It is possible to pass more than one argument into an arrow function.

// multiplies the first input value by the second and returns it
const multiplier = (item, multi) => item * multi;

Instructions

Rewrite the myConcat function which appends contents of arr2 to arr1 so that the function uses arrow function syntax.

Tests

tests:
  - text: User did replace <code>var</code> keyword.
    testString: getUserInput => assert(!getUserInput('index').match(/var/g));
  - text: <code>myConcat</code> should be a constant variable (by using <code>const</code>).
    testString: getUserInput => assert(getUserInput('index').match(/const\s+myConcat/g));
  - text: <code>myConcat</code> should be a function
    testString: assert(typeof myConcat === 'function');
  - text: <code>myConcat()</code> returns the correct <code>array</code>
    testString: assert(() => { const a = myConcat([1], [2]); return a[0] == 1 && a[1] == 2; });
  - text: <code>function</code> keyword was not used.
    testString: getUserInput => assert(!getUserInput('index').match(/function/g));

Challenge Seed

var myConcat = function(arr1, arr2) {
  "use strict";
  return arr1.concat(arr2);
};
// test your code
console.log(myConcat([1, 2], [3, 4, 5]));

Solution

const myConcat = (arr1, arr2) =>  {
  "use strict";
  return arr1.concat(arr2);
};
// test your code
console.log(myConcat([1, 2], [3, 4, 5]));

2.1 KiB Raw Blame History