lodash : how to loop with between a start value and end value

Question

I've a for loop in javascript shown below. How to convert it to lodash for loop? In such scenarios using lodash is advantageous over javascript for loop?

I've not used lodash much. Hence please advice.

for (var start = b, i = 0; start < end; ++i, ++start) {
// code goes here
}

Answer 1

You can use lodash range
https://lodash.com/docs/4.17.4#range

_.range(5, 10).forEach((current, index, range) => {
    console.log(current, index, range)
})

// 5, 0, [5, 6, 7, 8, 9, 10]
// 6, 1, [5, 6, 7, 8, 9, 10]
// 7, 2, [5, 6, 7, 8, 9, 10]
// 8, 3, [5, 6, 7, 8, 9, 10]
// 9, 4, [5, 6, 7, 8, 9, 10]
// 10, 5, [5, 6, 7, 8, 9, 10]

Answer 2

I will imagine that b = 3 and end = 10 if I run your code and print the variables here is what I will get:

var b = 3;
var end = 10;

for (var start = b, i = 0; start < end; ++i, ++start) {
  console.log(start, i);
}

> 3 0
> 4 1
> 5 2
> 6 3
> 7 4
> 8 5
> 9 6

To perform this with lodash (or underscore) I will first generate an array with range then iterate over it and gets the index on each iteration.

Here is the result

var b = 3;
var end = 10;

// this will generate an array [ 3, 4, 5, 6, 7, 8, 9 ]
var array = _.range(b, end); 

// now I iterate over it
_.each(array, function (value, key) {
  console.log(value, key);
});

And you will get the same result. The complexity is the same as the previous one (so no performance issue).