Definition
Scoping in programming is the concept of creating isolated code blocks, very similar to the use of paragraphs to discuss different contexts of a story.
Example
Let's look at some examples in code:
01:
02: var fruits = ['Apple', 'Banana', 'Cherry', 'Orange', 'Mango']
03:
04: var numberOfFruits = fruits.length
05:
06: for(var count = 0; numberOfFruits > count; count++) {
07: printer(fruits[count]) // <== output below:
08: }
09:
10: console.log("done")
11:
12: // output:
13: // Apple 5
14: // Banana 6
15: // Cherry 6
16: // Orange 6
17: // Mango 5
18: // done
19: function printer(item) {
20: console.log(item, item.length);
21: }
In the above code, we see the line printer(fruits[count])
(line 07) nested within a for
loop. The for loop sets the scope and everything within it is done within context.
That means until the for loop is done the console log on line 10 will not execute. There is a second context which is within the printer function. Anything that happens within that function will stay there unless otherwise specified like console.log its results.
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