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Code Issues Packages Projects Releases Wiki Activity

content(docs): update JS variables for clarity

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This commit is contained in:
Dhanush Adithya
2020-07-24 11:22:42 -04:00
committed by Jean-Philippe Sirois
parent 8f28201f6a
commit defc87a36e
1 changed files with 7 additions and 7 deletions
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src/content/resources/language/javascript/variables.md
+7 -7
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@@ -33,7 +33,7 @@ console.log(myVar);
## Dynamic Types ## Dynamic Types
Variables in Javascript do not have explicit types, as some other languages (eg: Java) do. This means that when declaring a variable, you only use `name = value`, and don't need to add a type as well. The type is automatically chosen based on the value. Variables in Javascript do not have explicit types, as some other languages (eg: Java, C++) do. This means that when declaring a variable, you only use `name = value`, and don't need to add a type as well. The type is automatically chosen based on the value.
```js ```js
let myString = "Hello"; let myString = "Hello";
@@ -76,10 +76,10 @@ myArray.push(5);
console.log(myArray); // [1,2,3,4,5] console.log(myArray); // [1,2,3,4,5]
const myObj = { foo: "bar" }; const myObj = { foo: "bar" };
console.log(myObj); // {foo: bar} console.log(myObj); // {foo: "bar"}
myObj.foo = "re-assigned"; myObj.foo = "re-assigned";
console.log(myObj); // {foo: re-assigned} console.log(myObj); // {foo: "re-assigned"}
``` ```
This, however, will still not work: This, however, will still not work:
@@ -87,7 +87,7 @@ This, however, will still not work:
```js ```js
const myArray = [1, 2, 3]; const myArray = [1, 2, 3];
myArray = [1, 2, 3, 4, 5]; // Error: myArray has already been defined myArray = [1, 2, 3, 4, 5]; // Error: Assignment to constant variable
``` ```
## What about var? ## What about var?
@@ -118,12 +118,12 @@ This is fixed using `let`
for (let i = 0; i < 5; i++) { for (let i = 0; i < 5; i++) {
console.log(i); console.log(i);
} }
console.log(i); // Error: i is undefined console.log(i); // Error: i is not defined
if (true) { if (true) {
let myVar = "test"; let myVar = "test";
} }
console.log(myVar); // Error: myVar is undefined console.log(myVar); // Error: myVar is not defined
``` ```
However, if the above code was in a function, this would not be the case. In the case of a function, the variable will be scoped to the given function, and not accessible outside it. Eg: However, if the above code was in a function, this would not be the case. In the case of a function, the variable will be scoped to the given function, and not accessible outside it. Eg:
@@ -132,7 +132,7 @@ However, if the above code was in a function, this would not be the case. In the
function myFunction() { function myFunction() {
var myVar = "test"; var myVar = "test";
} }
console.log(myVar); // Error: test is undefined console.log(myVar); // Error: test is not defined
``` ```
This can cause confusing behaviour, as `var` has different scoping behaviour depending on if its in a function or not. This is solved by using `let` or `const`. This can cause confusing behaviour, as `var` has different scoping behaviour depending on if its in a function or not. This is solved by using `let` or `const`.