JavaScript for loop closure issue

Question

I am adding all categories after ticking them to true if they exists in selected categories of result but it combines previous categories results with current one. I tried closure but it doesn't give me fresh object. Check out fiddle.

var allCatsResult = [{"id":1},{"id":2}, {"id":3}, ... ];
var catsArray = [1, 2] // Array of ids from allCatsResult 
var result = [
 {"id":1, selectedCategories:[{"id":1},{"id":2}]},
 {"id":2, selectedCategories:[{"id":4},{"id":5}]},
 ... 
 ];
for (var i = 0; i < results.length; i++) {
 var tmp = allCatsResult; // tried to add function form here didn't work
 for (var k = 0; k < results[i].selectedCategories.length; k++) {
 var index = catsArray.indexOf(results[i].selectedCategories[k].category_id); 
 if(index !== -1) {
 tmp[index].ticked = true;
 }
 } 
 results[i].categories = tmp;
}

Above code gives combined result for ticked = true for all categories in each result.

• Paul Fitzgerald: should it not be results.length as that is the name of your array?
• Shreejibawa: @PaulFitzgerald fixed typo.
• webduvet: where is the closure? what the result should be?
• Shreejibawa: @webduvet : each result should have all categories but for selected categories there should be ticked = true
• Shreejibawa: @charlietfl : please see fiddle result and inspect categories in each object.

Answer 1

You need to copy/clone the array of objects, or you're manipulating the original. There are a few ways apparently. I chose the following:

var tmp = JSON.parse(JSON.stringify(allCatsResult));

This will create a new array of objects in tmp, and it will correctly only modify the clone.

• charlietfl: why? indexOf() returns -1 if not found.
• Shreejibawa: I never get null so I will just skip this one.
• Mackan: @Shreejibawa I hope I can make up my past mistake with this