javascript - Remove a Single Object from a Javascript Object

Question

How do I remove one item based on both the courseID and endDate from the following javascript object?

    window.MyCheckedCourses = [
        { courseID: '123', endDate: '6/7/2010' },
        { courseID: '123', endDate: '3/9/2003' },
        { courseID: '456', endDate: '3/9/2003' }  
    ]; 

Answer 1

Iteration is a must. You have to use .splice() to remove corresponding item and break the for loop.

var i, id = '123', date = '6/7/2010';
for(var i = 0, il = MyCheckedCourses.length;i<il;i++) {
    if(MyCheckedCourses[i].courseID == id && MyCheckedCourses[i].endDate == date) {
        MyCheckedCourses.splice(i, 1);
        break;
    }
}

You can make a function and use it with parameters like this;

function remove(id, date) {
    for(var i = 0, il = MyCheckedCourses.length;i<il;i++) {
        if(MyCheckedCourses[i].courseID == id && MyCheckedCourses[i].endDate == date) {
            MyCheckedCourses.splice(i, 1);
            break;
        }
    }
}
// Example usage:
remove('123', '6/7/2010');

Edit after Ian's comment:

I assume that your collection have unique items. If not you have to iterate through all items and you have to do it backwards because if you remove an element from array it's index will change and iteration will not work correctly. So this function is a much more safer version;

function remove(id, date) {
    for(var i = MyCheckedCourses.length - 1;i >= 0;i--) {
        if(MyCheckedCourses[i].courseID == id && MyCheckedCourses[i].endDate == date) {
            MyCheckedCourses.splice(i, 1);
        }
    }
}
// Example usage:
remove('123', '6/7/2010');

Answer 2

You can delete an element from an array using splice: MyCheckedCourses.splice(index,length);

An example:

MyCheckedCourses=[0,1,2,3];
MyCheckedCourses.splice(1,1);

MyCheckedCourses is now: [0, 1, 3]

To find the index based on key values you can use:

// only returns the first found index
function findBy(arr,keys){
  var i = 0,match,len;
  for(i=0,len=arr.length;i<len;i++){
     match=true;
     for(key in keys){
       if(arr[i][key]!==keys[key]){
         match=false;
         break
       }
     }
     if(match===true){
       return i;
     }
  }
  return false;
}
var courses=[
    { courseID: '123', endDate: '6/7/2010' },
    { courseID: '123', endDate: '3/9/2003' },
    { courseID: '456', endDate: '3/9/2003' }  
  ];
var index = findBy(courses,
  {courseID:"123",
   endDate:"3/9/2003"}
);
if(index!==false){
  courses.splice(index,1);
}
console.log(courses);