Javascript: Specifying an Array's length and invoking a function

Question

I have a function that searches for a specified number in an array and returns the value that was searched for, the length of the array and the index in which the array was in.

I have 3 questions:

Is there a way to make a function that calls my console.log's so I don't have to write them every time I want to make a new array?
How do I get the first value of the array in this case? (The 'first array element' in my console.log)
Is there a way where I can make my array valued let's say 1 to "number" without typing out all those values in between? Because if I had a range from 1-400, typing all those values are going to hurt my fingers ;(.

Code:

function include(arr, obj) {
    for(var i=0; i< arr.length; i++) {
        if (arr[i] == obj)
            return [i, obj, arr.length];

    }
}

var a = include([1,2,3,4,5,6,7,8,9,10,11,12,13,14], 6); // true


    console.log("You searched for the value: " + a[1]);
    console.log("The length of the array is: " + a[2]);
    console.log("The Index of the value(" + a[1] + ") from " + "'first array element'" + " to " + (a[2]) + " is: " + a[0]);



console.log(include([1,2,3,4], 6)); // undefined

score 2 · Accepted Answer · answered Aug 10 '15 at 21:52

Per question:

console.log inside function. Return the search variable at the end of the function. Notice the change from a loop to indexOf.

function include(arr, obj) {
    var returned = -1;
    returned = arr.indexOf(obj); //get the index of the search criteria. It will return -1 if not found.

    console.log("You searched for the value: " + obj); //obj will be the search value
    if (returned != -1)
    {

        console.log("The length of the array is: " + arr.length); //arr.length gives us the length of the array;
        console.log("The Index of the value ("+obj+"): " + returned); //returned gives us the index value.
    }
    else
    {
        console.log("It was not found");
    }
    return returned;
}

var a = include([1,2,3,4,5,6,7,8,9,10,11,12,13,14], 6); // true

You can use the obj argument which is the search criteria and array.length to get the length of the array. I improved the functionality to use array.indexOf removing the need for a loop.
A for loop will do that:

var newArray = [];
for (var i = 0; i < 400; i++)
{
   array.push(i+1); //will push 400 values into the array.
}

score 1 · Answer 2 · edited May 23 '17 at 11:43

First: do you mean something like this?

function report(a) {
  console.log("You searched for the value: " + a[1]);
  console.log("The length of the array is: " + a[2]);
  console.log("The Index of the value(" + a[1] + ") from " + "'first array element'" + " to " + (a[2]) + " is: " + a[0]);
}

Second, to get the first array element you could access arr[0]. Why not return arr itself from include(), like so?

function include(arr, obj) {
  for(var i=0; i< arr.length; i++) {
    if (arr[i] == obj)
      return [i, obj, arr];
  }
}

Then:

console.log("The Index of the value(" + a[1] + ") from " + arr[0] + " to " + arr.length + " is: " + a[0]);

As for defining a range of numbers, JS has no native way to do this but you could use the Underscore library's _.range() method, or extend Javascript's Array like this!

Javascript: Specifying an Array's length and invoking a function

2 Answers2