Angular2 JSON Duplication Deletion - arrays

Question

I am working with a large JSON file holding information about instructors at my school. I want to be able to pull all the teachers names from this list so I can then put them into Firebase. However, whenever I loop over my JSON file and try to filter out all the duplicate teacher names I still end up with duplicates even when I try to do a second round of deletion. The JSON looks like this:
{
"Id": "1",
…
"Instructor": "name1, name2, name3",
…
},
{
"Id": "2",
…
"Instructor": "name1",
…
},
{
"Id": "3",
…
"Instructor": "name1, name2",
…
}
As seen above sometimes there is just one name, other times there are multiple. I handle this though in my logic but no matter what I still end up with duplicates. If anyone can help me come up with a way to solve this it would be greatly appreciated. I'll add my code that I have already below.
public remove_duplicates(arr: any[]): any[] {
let output: any[] = [];
for (let i = 0; i < arr.length; i++) {
let instruc: any[] = arr[i].Instructor.split(',');
for (let j = 0; j < instruc.length; j++) {
let push: boolean = true;
arr[i].Instructor = instruc[j];
for (let k = 0; k < output.length; k++) {
let i1: string = output[k].Instructor;
let i2: string = arr[i].Instructor;
if (i1.trim().localeCompare(i2.trim()) == 0) {
push = false;
}
}
if (push)
output.push(arr[i]);
}
}
console.log(output.length);
for (let k = 0; k < output.length; k++) {
for (let i = k + 1; i < output.length; i++) {
if (new String(output[i].Instructor).valueOf().trim()
=== new String(output[k].Instructor).valueOf().trim()) {
output.splice(i, 1);
}
}
}
for (let k = 0; k < output.length; k++) {
console.log(output[k].Instructor);
}
console.log(output.length);
return arr;
}
ngOnInit() {
this.http.get('courses.json').take(1)
.map((res: Response) => res.json())
.subscribe(
data => {
this.list = data;
},
err => console.log(err),
() => this.remove_duplicates(this.list)
);
}

Answer 1

There isn't anything specific to Angular 2 that you're trying to do here. This is just vanilla JS.
Try something like this:
public remove_duplicates(arr) {
let seen = {};
let uniqueInstructorNames = [];
arr.forEach(function(item) {
let instructorNames = item.Instructor.split(',');
Array.prototype.push.apply(uniqueInstructorNames, instructorNames.filter( name => {
return seen.hasOwnProperty(item) ? false : (seen[item] = true);
}));
});
return uniqueInstructorNames;
}