array from number code example

Example 1: create range array javascript

[...Array(10).keys()]
//=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Example 2: es6 create array with increasing number

Array.from(Array(10).keys())
//=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Example 3: javascript fill array with range

function range(start, end) {
  return Array(end - start + 1).fill().map((_, idx) => start + idx)
}
var result = range(9, 18); // [9, 10, 11, 12, 13, 14, 15, 16, 17, 18]
console.log(result);

Example 4: generate array range

for (i of range(1, 5)) {
    console.log(i);
}
/* Output
 * 1 2 3 4 5 */

[...range(1, 5)] // [1, 2, 3, 4, 5]

Example 5: number to array js

const arrayOfDigits = numToSeparate.toString().split("");

Example 6: array from js

//Array.from() lets you create Arrays from array-like objects
//(objects with a length property and indexed elements);
//and also:

//More clearly, Array.from(obj, mapFn, thisArg)
//has the same result as Array.from(obj).map(mapFn, thisArg), 
//except that it does not create an intermediate array.
//Basically, it's a declaration that overrides the length property of the method
//(so that it has to be used with the same name length),
//setting it with the same value of the given variable. 
//The values are still undefined, it's just a different notation. Take a look:

console.log(Array.from(length, (_,i) => i));
// It doesn't works with non-iterables
// In this case we are passing an integer

console.log(Array.from({LENGTH}, (_,i) => i));
// It doesn't work with a property name different from "length"

console.log(Array.from({length}, (_,i) => i));
// It works because overrides the .length property of the array
// The method Array.from() assumes that the property...
// ...is referring to an iterable (also if not declared) 

console.log(Array.from(Array(length), (_,i) => i));
// This is the demonstration of the above assertion
// In this case we are using a declared array through...
// ...an instance of the straight method Array()...
// ...that accepts an integer as value

//in case any one reads this a got this from er0s in edabit