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access-array-data-with-indexes.english.md
access-multi-dimensional-arrays-with-indexes.english.md
accessing-nested-arrays.english.md
accessing-nested-objects.english.md
accessing-object-properties-with-bracket-notation.english.md
accessing-object-properties-with-dot-notation.english.md
accessing-object-properties-with-variables.english.md
add-new-properties-to-a-javascript-object.english.md
add-two-numbers-with-javascript.english.md
adding-a-default-option-in-switch-statements.english.md
appending-variables-to-strings.english.md
assignment-with-a-returned-value.english.md
build-javascript-objects.english.md
chaining-if-else-statements.english.md
comment-your-javascript-code.english.md
comparison-with-the-equality-operator.english.md
comparison-with-the-greater-than-operator.english.md
comparison-with-the-greater-than-or-equal-to-operator.english.md
comparison-with-the-inequality-operator.english.md
comparison-with-the-less-than-operator.english.md
comparison-with-the-less-than-or-equal-to-operator.english.md
comparison-with-the-strict-equality-operator.english.md
comparison-with-the-strict-inequality-operator.english.md
comparisons-with-the-logical-and-operator.english.md
comparisons-with-the-logical-or-operator.english.md
compound-assignment-with-augmented-addition.english.md
compound-assignment-with-augmented-division.english.md
compound-assignment-with-augmented-multiplication.english.md
compound-assignment-with-augmented-subtraction.english.md
concatenating-strings-with-plus-operator.english.md
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constructing-strings-with-variables.english.md
count-backwards-with-a-for-loop.english.md
counting-cards.english.md
create-decimal-numbers-with-javascript.english.md
declare-javascript-variables.english.md
declare-string-variables.english.md
decrement-a-number-with-javascript.english.md
delete-properties-from-a-javascript-object.english.md
divide-one-decimal-by-another-with-javascript.english.md
divide-one-number-by-another-with-javascript.english.md
escape-sequences-in-strings.english.md
escaping-literal-quotes-in-strings.english.md
find-the-length-of-a-string.english.md
finding-a-remainder-in-javascript.english.md
generate-random-fractions-with-javascript.english.md
generate-random-whole-numbers-with-javascript.english.md
generate-random-whole-numbers-within-a-range.english.md
global-scope-and-functions.english.md
global-vs.-local-scope-in-functions.english.md
golf-code.english.md
increment-a-number-with-javascript.english.md
initializing-variables-with-the-assignment-operator.english.md
introducing-else-if-statements.english.md
introducing-else-statements.english.md
iterate-odd-numbers-with-a-for-loop.english.md
iterate-through-an-array-with-a-for-loop.english.md
iterate-with-javascript-do...while-loops.english.md
iterate-with-javascript-for-loops.english.md
iterate-with-javascript-while-loops.english.md
local-scope-and-functions.english.md
logical-order-in-if-else-statements.english.md
manipulate-arrays-with-pop.english.md
manipulate-arrays-with-push.english.md
manipulate-arrays-with-shift.english.md
manipulate-arrays-with-unshift.english.md
manipulating-complex-objects.english.md
modify-array-data-with-indexes.english.md
multiple-identical-options-in-switch-statements.english.md
multiply-two-decimals-with-javascript.english.md
multiply-two-numbers-with-javascript.english.md
nest-one-array-within-another-array.english.md
nesting-for-loops.english.md
passing-values-to-functions-with-arguments.english.md
practice-comparing-different-values.english.md
profile-lookup.english.md
quoting-strings-with-single-quotes.english.md
record-collection.english.md
replacing-if-else-chains-with-switch.english.md
return-a-value-from-a-function-with-return.english.md
return-early-pattern-for-functions.english.md
returning-boolean-values-from-functions.english.md
selecting-from-many-options-with-switch-statements.english.md
shopping-list.english.md
stand-in-line.english.md
store-multiple-values-in-one-variable-using-javascript-arrays.english.md
storing-values-with-the-assignment-operator.english.md
subtract-one-number-from-another-with-javascript.english.md
testing-objects-for-properties.english.md
understand-string-immutability.english.md
understanding-boolean-values.english.md
understanding-case-sensitivity-in-variables.english.md
understanding-undefined-value-returned-from-a-function.english.md
understanding-uninitialized-variables.english.md
updating-object-properties.english.md
use-bracket-notation-to-find-the-first-character-in-a-string.english.md
use-bracket-notation-to-find-the-last-character-in-a-string.english.md
use-bracket-notation-to-find-the-nth-character-in-a-string.english.md
use-bracket-notation-to-find-the-nth-to-last-character-in-a-string.english.md
use-conditional-logic-with-if-statements.english.md
use-multiple-conditional-ternary-operators.english.md
use-the-conditional-ternary-operator.english.md
use-the-parseint-function-with-a-radix.english.md
use-the-parseint-function.english.md
using-objects-for-lookups.english.md
word-blanks.english.md
write-reusable-javascript-with-functions.english.md
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111 lines
2.3 KiB
Markdown
111 lines
2.3 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244bf
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title: Local Scope and Functions
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challengeType: 1
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---
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## Description
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<section id='description'>
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Variables which are declared within a function, as well as the function parameters have <dfn>local</dfn> scope. That means, they are only visible within that function.
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Here is a function <code>myTest</code> with a local variable called <code>loc</code>.
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<blockquote>function myTest() {<br> var loc = "foo";<br> console.log(loc);<br>}<br>myTest(); // logs "foo"<br>console.log(loc); // loc is not defined</blockquote>
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<code>loc</code> is not defined outside of the function.
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</section>
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## Instructions
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<section id='instructions'>
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Declare a local variable <code>myVar</code> inside <code>myLocalScope</code>. Run the tests and then follow the instructions commented out in the editor.
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<strong>Hint</strong><br>Refreshing the page may help if you get stuck.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: No global <code>myVar</code> variable
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testString: 'assert(typeof myVar === "undefined", "No global <code>myVar</code> variable");'
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- text: Add a local <code>myVar</code> variable
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testString: 'assert(/var\s+myVar/.test(code), "Add a local <code>myVar</code> variable");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function myLocalScope() {
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'use strict'; // you shouldn't need to edit this line
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console.log(myVar);
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}
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myLocalScope();
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// Run and check the console
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// myVar is not defined outside of myLocalScope
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console.log(myVar);
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// Now remove the console log line to pass the test
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```
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</div>
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### Before Test
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<div id='js-setup'>
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```js
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var logOutput = "";
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var originalConsole = console
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function capture() {
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var nativeLog = console.log;
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console.log = function (message) {
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logOutput = message;
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if(nativeLog.apply) {
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nativeLog.apply(originalConsole, arguments);
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} else {
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var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
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nativeLog(nativeMsg);
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}
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};
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}
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function uncapture() {
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console.log = originalConsole.log;
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}
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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console.info('after the test');
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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function myLocalScope() {
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'use strict';
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var myVar;
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console.log(myVar);
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}
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myLocalScope();
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```
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</section>
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