JavaScript ES6 Q&A: Complex Problems Simple Solutions

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Javascript is one of the hottest programming languages of all time. For beginners or even mid-level programmers, this is a simple guide to build logic with most common but powerful functions of JavaScript ES6.

let foo = 1; // foo = true; // foo = 'a'; // foo = "Hello";

How to determine the data type of a variable?

return typeof(foo);

Alternatively, comparing datatypes:

return typeof(foo) === 'boolean';
// This will return true if value of foo is boolean else will return false.

How to remove duplicates from an array?

let data = [“apple”, “orange”, “apple”, “banana”, “banana”, “apple”];
distinct_array = […new Set(data)];
// distinct_array = ["apple", "orange", "banana"]

Alternative Method:

distinct_array = data.filter((item,pos,self) => self.indexOf(item) === pos);

How to check if an item is present in the array?

let data = [“blue”, “pink”, “red”, “green”];
return data.indexOf(“yellow”) ≤ -1
// will return true as yellow is not present in the array

— — — Array of objects — — —

let planets = [
{"name": "mercury", "position": 1, "colour": "grey"},
{"name": "venus", "position": 2, "colour": "Brown…