dry-forloop

A drier version of JavaScript's existing forLoop. Like forEach, but with parameters for start, operator, length, and iterator!

This is an open-source project. We are accepting PRs.

Syntax

arr.forDry([ start [, operator [, length [, iterator]]]], 
    function callback(element [, index [, array]]){
        //your iterator
    }
);

Parameters

• start (Optional)

Defaults to 0

Variable representing the starting index of the iteration. Must be a number greater then 0.

• operator (Optional)

Defaults to '<='

Variable representing the operator involved in the current index position comparison with length. Must be entered as a string.

Options:  
'<'  
'>'  
'<='  
'>='  
'==='  
'!=='  

• length (Optional)

Defaults to 'length - 1'

Variable representing the length involved in the current index position comparison with length. May be a string or number.

Options:  
'length - 1'  
'length'  
Any number  

• iterator (Optional)

Defaults to '++'

Variable representing the stepwise postive/negative direction of the iteration. Must be entered as a string.

Options:  
'++'  
'--'  

• callback
  Function to execute on each element, taking three arguments:

  element
  The current element being processed in the array.

  index (Optional)
  The index of the current element being processed in the array.

  array (Optional)
  The array forDry() was called upon.

Return value

Defined by user's code in the callback and subsequent return.

Description

.forDry() calls a provided callback function once for each element in an array.

The callback is invoked with three arguments:

the element of the array
the index of the element
the array itself

forDry() may or may not mutate the array on which it is called depending on use of the callback. It should be noted that the code does not mutate the Array.prototype itself. Rather, it simply utilizes the given parameters to mutate a standard forLoop and applies these changes to the array variable.

Example Code

const forDry = require('dry-forloop'); 

let array = [1, 2, 3, 4, 5], solution = [];  

Basic forLoop

array.forDry((e, i) => {
    console.log(e, i);
    }
);  

Expected return:   
0 1  
1 2  
2 3  
3 4  
4 5  

Start

array.forDry(1, null, null, null, (e, i) => {
    console.log(e, i);
    }
);

Expected return:   
1 2
2 3
3 4
4 5

Operator

array.forDry(null, '!==', null, null, (e, i) => {
    console.log(e, i);
    }
);

Expected return:   
0 1
1 2
2 3
3 4

Length

array.forDry(null, null, 'length', null, (e, i) => {
    console.log(e, i);
    }
);

Expected return:   
0 1
1 2
2 3
3 4
4 5
5 undefined

Iterator

array.forDry(5, '>', 0, '--', (e, i) => {
    console.log(e, i);
    }
);

Expected return:   
5 undefined
4 5
3 4
2 3
1 2 

Nested

array.forDry((e) => {
    array.forDry(1, (f) => {
        solution.push(e + f);
    })
});

console.log(solution);

Expected return: 
[ 3, 4, 5, 6, 4, 5, 6, 7, 5, 6, 7, 8, 6, 7, 8, 9, 7, 8, 9, 10 ]