CODEWITHSUNDEEP
javascriptarraysloopsforeacharray.prototype.map
On the_job
On the_job

Reputation: 19

How to loop an Array with JavaScript

So I am fairly new to JavaScript. I have a problem I need to solve. I came this far but don't know how to go further. I need to take the code below and execute the same result without using the for-loop.

 for(var i = 0; i < 7; i++)
    {
    console.log([...Array(i)].map(x => '*').join(""));
    }

Upvotes: 1

Views: 79

Answers (4)

GottZ
GottZ

Reputation: 4947

[...Array(7)] // this will create a low performance array with seven entries
.map ( // both map and forEach provide three arguments: (value, index, array)
       // in this case we care about the index to know where in the loop we are.
  (x, i) => "*".repeat(i) // look up String.prototype.repeat.
)
.forEach(x => console.log(x)) // then for each iteration, call console.log

Upvotes: 1

prasana kannan
prasana kannan

Reputation: 676

Recursively call it to perform the same, 

function drawStar(times) {
    function drawRecursive(i) {
        if (i === times) return;
        console.log(Array(i).fill("*").join(""));
        drawRecursive(++i);
    }
    drawRecursive(1);
}

drawStar(7);

Upvotes: 0

Ivan Ignatiev
Ivan Ignatiev

Reputation: 1099

I propose to use the same logic that you are using already. .map argument function has index parameter.

console.log([...Array(7)].map((x,i) => [...Array(i)].map(x => "*").join("")).join("\r\n"))

In the situations when you are not authorized to use loops you have recursive function option and Array.forEach()

Upvotes: 1

Jessica
Jessica

Reputation: 1

I recommend reviewing the documentation on arrays. To accomplish this without using a for loop, you could utilize the Array.forEach() method.

See MDN documentation here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

Upvotes: 0

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