freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-an.../basic-javascript/practice-comparing-differen...

81 lines
1.9 KiB
Markdown

---
id: 599a789b454f2bbd91a3ff4d
title: Practice comparing different values
challengeType: 1
videoUrl: 'https://scrimba.com/c/cm8PqCa'
forumTopicId: 301174
dashedName: practice-comparing-different-values
---
# --description--
In the last two challenges, we learned about the equality operator (`==`) and the strict equality operator (`===`). Let's do a quick review and practice using these operators some more.
If the values being compared are not of the same type, the equality operator will perform a type conversion, and then evaluate the values. However, the strict equality operator will compare both the data type and value as-is, without converting one type to the other.
**Examples**
```js
3 == '3' // returns true because JavaScript performs type conversion from string to number
3 === '3' // returns false because the types are different and type conversion is not performed
```
**Note**
In JavaScript, you can determine the type of a variable or a value with the `typeof` operator, as follows:
```js
typeof 3 // returns 'number'
typeof '3' // returns 'string'
```
# --instructions--
The `compareEquality` function in the editor compares two values using the equality operator. Modify the function so that it returns "Equal" only when the values are strictly equal.
# --hints--
`compareEquality(10, "10")` should return "Not Equal"
```js
assert(compareEquality(10, '10') === 'Not Equal');
```
`compareEquality("20", 20)` should return "Not Equal"
```js
assert(compareEquality('20', 20) === 'Not Equal');
```
You should use the `===` operator
```js
assert(code.match(/===/g));
```
# --seed--
## --seed-contents--
```js
// Setup
function compareEquality(a, b) {
if (a == b) { // Change this line
return "Equal";
}
return "Not Equal";
}
compareEquality(10, "10");
```
# --solutions--
```js
function compareEquality(a,b) {
if (a === b) {
return "Equal";
}
return "Not Equal";
}
```