Is a set of object which is listed in a specific order?

The Set object lets you store unique values of any type, whether primitive values or object references.

Description

Set objects are collections of values. A value in the Set may only occur once; it is unique in the Set's collection. You can iterate through the elements of a set in insertion order. The insertion order corresponds to the order in which each element was inserted into the set by the

for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
1 method successfully (that is, there wasn't an identical element already in the set when
for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
1 was called).

The specification requires sets to be implemented "that, on average, provide access times that are sublinear on the number of elements in the collection". Therefore, it could be represented internally as a hash table (with O(1) lookup), a search tree (with O(log(N)) lookup), or any other data structure, as long as the complexity is better than O(N).

Value equality

Value equality is based on the SameValueZero algorithm. (It used to use SameValue, which treated

for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
3 and
for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
4 as different. Check browser compatibility.) This means
for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
5 is considered the same as
for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
5 (even though
for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
7) and all other values are considered equal according to the semantics of the
for (const item of mySet1) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.keys()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

for (const item of mySet1.values()) {
  console.log(item);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// key and value are the same here
for (const [key, value] of mySet1.entries()) {
  console.log(key);
}
// 1, "some text", { "a": 1, "b": 2 }, { "a": 1, "b": 2 }, 5

// Convert Set object to an Array object, with Array.from
const myArr = Array.from(mySet1) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}, 5]

// the following will also work if run in an HTML document
mySet1.add(document.body)
mySet1.has(document.querySelector('body')) // true

// converting between Set and Array
const mySet2 = new Set([1, 2, 3, 4]);
console.log(mySet2.size); // 4
console.log([...mySet2]); // [1, 2, 3, 4]

// intersect can be simulated via
const intersection = new Set([...mySet1].filter((x) => mySet2.has(x)));

// difference can be simulated via
const difference = new Set([...mySet1].filter((x) => !mySet2.has(x)));

// Iterate set entries with forEach()
mySet2.forEach((value) => {
  console.log(value);
});
// 1
// 2
// 3
// 4
8 operator.

Performance

The Set

function isSuperset(set, subset) {
  for (const elem of subset) {
    if (!set.has(elem)) {
      return false;
    }
  }
  return true;
}

function union(setA, setB) {
  const _union = new Set(setA);
  for (const elem of setB) {
    _union.add(elem);
  }
  return _union;
}

function intersection(setA, setB) {
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

function symmetricDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    if (_difference.has(elem)) {
      _difference.delete(elem);
    } else {
      _difference.add(elem);
    }
  }
  return _difference;
}

function difference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

// Examples
const setA = new Set([1, 2, 3, 4])
const setB = new Set([2, 3])
const setC = new Set([3, 4, 5, 6])

isSuperset(setA, setB)          // returns true
union(setA, setC)               // returns Set {1, 2, 3, 4, 5, 6}
intersection(setA, setC)        // returns Set {3, 4}
symmetricDifference(setA, setC) // returns Set {1, 2, 5, 6}
difference(setA, setC)          // returns Set {1, 2}
0 method checks if a value is in a Set object, using an approach that is, on average, quicker than testing most of the elements that have previously been added to the Set object. In particular, it is, on average, faster than the
function isSuperset(set, subset) {
  for (const elem of subset) {
    if (!set.has(elem)) {
      return false;
    }
  }
  return true;
}

function union(setA, setB) {
  const _union = new Set(setA);
  for (const elem of setB) {
    _union.add(elem);
  }
  return _union;
}

function intersection(setA, setB) {
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

function symmetricDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    if (_difference.has(elem)) {
      _difference.delete(elem);
    } else {
      _difference.add(elem);
    }
  }
  return _difference;
}

function difference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

// Examples
const setA = new Set([1, 2, 3, 4])
const setB = new Set([2, 3])
const setC = new Set([3, 4, 5, 6])

isSuperset(setA, setB)          // returns true
union(setA, setC)               // returns Set {1, 2, 3, 4, 5, 6}
intersection(setA, setC)        // returns Set {3, 4}
symmetricDifference(setA, setC) // returns Set {1, 2, 5, 6}
difference(setA, setC)          // returns Set {1, 2}
3 method when an
function isSuperset(set, subset) {
  for (const elem of subset) {
    if (!set.has(elem)) {
      return false;
    }
  }
  return true;
}

function union(setA, setB) {
  const _union = new Set(setA);
  for (const elem of setB) {
    _union.add(elem);
  }
  return _union;
}

function intersection(setA, setB) {
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

function symmetricDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    if (_difference.has(elem)) {
      _difference.delete(elem);
    } else {
      _difference.add(elem);
    }
  }
  return _difference;
}

function difference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

// Examples
const setA = new Set([1, 2, 3, 4])
const setB = new Set([2, 3])
const setC = new Set([3, 4, 5, 6])

isSuperset(setA, setB)          // returns true
union(setA, setC)               // returns Set {1, 2, 3, 4, 5, 6}
intersection(setA, setC)        // returns Set {3, 4}
symmetricDifference(setA, setC) // returns Set {1, 2, 5, 6}
difference(setA, setC)          // returns Set {1, 2}
4 object has a
function isSuperset(set, subset) {
  for (const elem of subset) {
    if (!set.has(elem)) {
      return false;
    }
  }
  return true;
}

function union(setA, setB) {
  const _union = new Set(setA);
  for (const elem of setB) {
    _union.add(elem);
  }
  return _union;
}

function intersection(setA, setB) {
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

function symmetricDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    if (_difference.has(elem)) {
      _difference.delete(elem);
    } else {
      _difference.add(elem);
    }
  }
  return _difference;
}

function difference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

// Examples
const setA = new Set([1, 2, 3, 4])
const setB = new Set([2, 3])
const setC = new Set([3, 4, 5, 6])

isSuperset(setA, setB)          // returns true
union(setA, setC)               // returns Set {1, 2, 3, 4, 5, 6}
intersection(setA, setC)        // returns Set {3, 4}
symmetricDifference(setA, setC) // returns Set {1, 2, 5, 6}
difference(setA, setC)          // returns Set {1, 2}
5 equal to a Set object's
function isSuperset(set, subset) {
  for (const elem of subset) {
    if (!set.has(elem)) {
      return false;
    }
  }
  return true;
}

function union(setA, setB) {
  const _union = new Set(setA);
  for (const elem of setB) {
    _union.add(elem);
  }
  return _union;
}

function intersection(setA, setB) {
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

function symmetricDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    if (_difference.has(elem)) {
      _difference.delete(elem);
    } else {
      _difference.add(elem);
    }
  }
  return _difference;
}

function difference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

// Examples
const setA = new Set([1, 2, 3, 4])
const setB = new Set([2, 3])
const setC = new Set([3, 4, 5, 6])

isSuperset(setA, setB)          // returns true
union(setA, setC)               // returns Set {1, 2, 3, 4, 5, 6}
intersection(setA, setC)        // returns Set {3, 4}
symmetricDifference(setA, setC) // returns Set {1, 2, 5, 6}
difference(setA, setC)          // returns Set {1, 2}
7.

Constructor

function isSuperset(set, subset) {
  for (const elem of subset) {
    if (!set.has(elem)) {
      return false;
    }
  }
  return true;
}

function union(setA, setB) {
  const _union = new Set(setA);
  for (const elem of setB) {
    _union.add(elem);
  }
  return _union;
}

function intersection(setA, setB) {
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

function symmetricDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    if (_difference.has(elem)) {
      _difference.delete(elem);
    } else {
      _difference.add(elem);
    }
  }
  return _difference;
}

function difference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

// Examples
const setA = new Set([1, 2, 3, 4])
const setB = new Set([2, 3])
const setC = new Set([3, 4, 5, 6])

isSuperset(setA, setB)          // returns true
union(setA, setC)               // returns Set {1, 2, 3, 4, 5, 6}
intersection(setA, setC)        // returns Set {3, 4}
symmetricDifference(setA, setC) // returns Set {1, 2, 5, 6}
difference(setA, setC)          // returns Set {1, 2}
8

Creates a new Set object.

Static properties

const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
0

The constructor function that is used to create derived objects.

Instance properties

const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
1

The initial value of the

const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
2 property is the string
const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
3. This property is used in
const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
4.

const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
5

Returns the number of values in the Set object.

Instance methods

const myArray = ['value1', 'value2', 'value3'];

// Use the regular Set constructor to transform an Array into a Set
const mySet = new Set(myArray);

mySet.has('value1')     // returns true

// Use the spread syntax to transform a set into an Array.
console.log([...mySet]); // Will show you exactly the same Array as myArray
7

Inserts a new element with a specified value in to a Set object, if there isn't an element with the same value already in the Set.

// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
0

Removes all elements from the Set object.

// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
2

Removes the element associated to the

// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
3 and returns a boolean asserting whether an element was successfully removed or not.
// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
4 will return
// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
5 afterwards.

// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
6

Returns a boolean asserting whether an element is present with the given value in the Set object or not.

// Use to remove duplicate elements from the array

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

console.log([...new Set(numbers)])

// [2, 3, 4, 5, 6, 7, 32]
8

Returns a new iterator object that yields the values for each element in the Set object in insertion order.

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
0

Returns a new iterator object that yields the values for each element in the Set object in insertion order.

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
2

An alias for

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
0.

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
4

Returns a new iterator object that contains an array of

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
5 for each element in the Set object, in insertion order.

This is similar to the

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
7 object, so that each entry's key is the same as its value for a Set.

const text = 'India';

const mySet = new Set(text);  // Set(5) {'I', 'n', 'd', 'i', 'a'}
mySet.size  // 5

//case sensitive & duplicate omission
new Set("Firefox")  // Set(7) { "F", "i", "r", "e", "f", "o", "x" }
new Set("firefox")  // Set(6) { "f", "i", "r", "e", "o", "x" }
9

Calls

const array = Array
  .from(document.querySelectorAll('[id]'))
  .map((e) => e.id);

const set = new Set(array);
console.assert(set.size === array.length);
0 once for each value present in the Set object, in insertion order. If a
const array = Array
  .from(document.querySelectorAll('[id]'))
  .map((e) => e.id);

const set = new Set(array);
console.assert(set.size === array.length);
2 parameter is provided, it will be used as the
const array = Array
  .from(document.querySelectorAll('[id]'))
  .map((e) => e.id);

const set = new Set(array);
console.assert(set.size === array.length);
3 value for each invocation of
const array = Array
  .from(document.querySelectorAll('[id]'))
  .map((e) => e.id);

const set = new Set(array);
console.assert(set.size === array.length);
0.

What is the set of object or numbers which is listed in a specific order one after another?

A sequence is a list of numbers in a certain order. Each number in a sequence is called a term . Each term in a sequence has a position (first, second, third and so on). For example, consider the sequence {5,15,25,35,…}

Is a pair of object taken in a specific order?

A permutation is an arrangement of objects in a definite order. The members or elements of sets are arranged here in a sequence or linear order. For example, the permutation of set A={1,6} is 2, such as {1,6}, {6,1}. As you can see, there are no other ways to arrange the elements of set A.

Which of the following is a set of numbers arranged in a specific order?

A sequence is defined as an arrangement of numbers in a particular order.

Is the order of listing the element in a set important?

The order of elements in the set does not matter. We could just as well write S = {N ader, Buchanan, Gore, Bush}. In general, two sets are the same if and only if they have exactly the same members. “Gore ∈ S” reads “Gore is a member of the set S.” “∈” means “is a member of” or “is in”.