I have two arrays of objects:
courses = [ { _id: 999, courseCode: "Eng1" },
{ _id: 777, courseCode: "Sci1" },
{ _id: 666, courseCode: "Eng2" },
{ _id: 888, courseCode: "Sci2" } ]
sectionCourses = [ { sectionCode: "1A", courseId: "999" },
{ sectionCode: "1A", courseId: "777" },
{ sectionCode: "2A", courseId: "666" },
{ sectionCode: "2A", courseId: "888" } ]
I want to filter the courses
array in such a way that it contains only the courses that are not in a section.
For example if I select section with sectionCode: "2A"
, the courses
array should only contain
courses = [ { _id: 999, courseCode: "Eng1" },
{ _id: 777, courseCode: "Sci1" },
{ _id: 888, courseCode: "Sci2" } ]
I tried to do this way:
courses = courses.filter(c => !(sectionCourses.includes(c._id)))
but I know this is incomplete because I can't figure out how to access courseId
in sectionCourses
.
Please help.
You can't use .includes()
method to find the whole object by its _id
, includes compares the whole objects and doesn't search for a specific property.
What you can do here is to get an array of courseIds
to be ignored based on the sectionCode
you provided, and then filter the courses that their _id
doesn't exist in this array of ids
:
function getCourses(catCode) {
var coursesIdstoIgnore = sectionCourses.filter(s => s.sectionCode === catCode).map(s => s.courseId);
return courses.filter(c => coursesIdstoIgnore.indexOf(c["_id"].toString()) == -1);
}
Demo:
var courses = [{
_id: 999,
courseCode: "Eng1"
},
{
_id: 777,
courseCode: "Sci1"
},
{
_id: 666,
courseCode: "Eng2"
},
{
_id: 888,
courseCode: "Sci2"
}
];
var sectionCourses = [{
sectionCode: "1A",
courseId: "999"
},
{
sectionCode: "1A",
courseId: "777"
},
{
sectionCode: "2A",
courseId: "666"
},
{
sectionCode: "2A",
courseId: "888"
}
];
function getCourses(catCode) {
var cousesIdstoIgnore = sectionCourses.filter(s => s.sectionCode === catCode).map(s => s.courseId);
console.log(cousesIdstoIgnore);
return courses.filter(c => cousesIdstoIgnore.indexOf(c["_id"].toString()) == -1);
}
var results = getCourses("2A");
console.log(results);