How do I make a function use a variable that was declared on another function JavaScript/jQuery

Question

So, I have a var named inimigo that is declared in function of a setInterval() but on another function named checkcolisions I want to get the positions of the inimigo so I can check the collision with him and bala where i can get the position of bala by declaring the function after the animate as you can see. After many tries, the ckeckcolision always says inimigo is not defined". How can I get the position of inimigo and check the collision with bala's position? If you have better ways to check the collision between the two please let me know, I will really accept them. Thanks for your time.

$(document).ready(function() {
    "use strict";
    $(document).on('keydown', function(e) {

        var kp = e.keyCode;
        var carro = $("#carro");
        var bala = $("#bala");
        e.preventDefault();



        if (kp === 37 && carro.position().left > -500) {
            carro.css("left", (carro.position().left - 7) + "px");
        }

        if (kp === 39 && carro.position().left < 350) {
            carro.css("left", (carro.position().left + 7) + "px");
        }

        if (kp === 32) {

            bala.show();
            bala.css('left', (carro.offset().left + 67) + "px");
            bala.css('top', (carro.offset().top - 20) + "px");


            bala.animate({
                "top": "-=100px"
            }, "fast", checkCollisions);

        }
    });

    var counter2 = 0;
    var j = setInterval(function() {


        var inimigo = $(".inimigo").clone();
        $('.jogo2').html(inimigo);

        inimigo.css('left', (Math.floor(Math.random() * 200) + 550));
        inimigo.css('top', "150px");



    }, 2000);

    function getPositions(disparo) {
        var $disparo = $(disparo);
        var pos = $disparo.position();
        var width = $disparo.width();
        var height = $disparo.height();
        return [
            [pos.left, pos.left + width],
            [pos.top, pos.top + height]
        ];
    }

    function comparePositions(p1, p2) {
        var x1 = p1[0] < p2[0] ? p1 : p2;
        var x2 = p1[0] < p2[0] ? p2 : p1;
        return x1[1] > x2[0] || x1[0] === x2[0] ? true : false;
    }


    function checkCollisions() {
        var disparo = inimigo;
        var pos = getPositions(disparo);

        var pos2 = getPositions(this);
        var horizontalMatch = comparePositions(pos[0], pos2[0]);
        var verticalMatch = comparePositions(pos[1], pos2[1]);
        var match = horizontalMatch && verticalMatch;
        if (match) {

            alert("score +1");
        }
    }

});

Possible duplicate of [What is the scope of variables in JavaScript?](https://stackoverflow.com/questions/500431/what-is-the-scope-of-variables-in-javascript) — Oen44, Jun 22 '17 at 12:53

score 1 · Answer 1 · edited Jun 22 '17 at 13:30

1

You need to declare a variable in an outer context that is accessible by both functions:

var inimigo = null;
var counter2 = 0;
var j = setInterval(function() {
  inimigo = $(".inimigo").clone();
  $('.jogo2').html(inimigo);
  inimigo.css('left', (Math.floor(Math.random() * 200) + 550));
  inimigo.css('top', "150px");
}, 2000);

edited Jun 22 '17 at 13:30

Milan Chheda

8,159
3
20
35

answered Jun 22 '17 at 12:51

Adder

5,708
1
28
56

score 0 · Answer 2 · answered Jun 22 '17 at 12:54

0

You can define inimigo variable globally so that you can access it any of the function. Whenever any function will access that variable, the recently changed value will be taken in consideration.

answered Jun 22 '17 at 12:54

Nirav Majevadiya

84
2
6

score 0 · Answer 3 · answered Jun 22 '17 at 13:14

You can have global variables. If you want to access method specific variable you can try this example e.g.`

function y(){
    var x = 10;
    return { 
        get : function(){ 
                return x;
            } 
    } 
}

` and you can access like

y().get();

How do I make a function use a variable that was declared on another function JavaScript/jQuery

3 Answers3