JavaScript Set Methods

new Set() method

Pass the array to new Set() Constructor:

Instance

// Create a Set
const letters = new Set(["a","b","c"]);

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add() method

Instance

letters.add("d");
letters.add("e");

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If the same element is added, only the first one will be saved:

Instance

letters.add("a");
letters.add("b");
letters.add("c");
letters.add("c");
letters.add("c");
letters.add("c");
letters.add("c");
letters.add("c");

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List Set elements

You can use for..of Loop through all Set elements (values):

Instance

// Create a Set
const letters = new Set(["a", "b", "c"]);
// List all elements
let text = "";
for (const x of letters) {
  text += x;
}

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has() method

If the specified value exists in the Set,has() The method returns true.

Instance

// Create a Set
const letters = new Set(["a", "b", "c"]);
// Does the Set contain "d"?
answer = letters.has("d");

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forEach() method

forEach() The method calls a function for each element of the Set:

Instance

// Create a Set
const letters = new Set(["a", "b", "c"]);
// List all entries
let text = "";
letters.forEach(function(value) {
  text += value;
});

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values() method

values() The method returns an iterator object containing the values of the Set:

Example 1

// Create a Set
const letters = new Set(["a", "b", "c"]);
// Get all values
const myIterator = letters.values();
// List all values
let text = "";
for (const entry of myIterator) {
  text += entry;
}

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Example 2

// Create a Set
const letters = new Set(["a", "b", "c"]);
// List all values
let text = "";
for (const entry of letters.values()) {
  text += entry;
}

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keys() method

keys() The method returns an iterator object containing the values of the Set:

Example 1

// Create a Set
const letters = new Set(["a", "b", "c"]);
// Create an iterator
const myIterator = letters.keys();
// List all elements
let text = "";
for (const x of myIterator) {
  text += x;
}

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Example 2

// Create a Set
const letters = new Set(["a", "b", "c"]);
// List all elements
let text = "";
for (const x of letters.keys()) {
  text += x;
}

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returns an array containing [

entries() The entries() methodvalue, value].

Example 1

// Create a Set
const letters = new Set(["a", "b", "c"]);
// Get all entries
const myIterator = letters.entries();
// List all entries
let text = "";
for (const entry of myIterator) {
  text += entry;
}

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Example 2

// Create a Set
const letters = new Set(["a", "b", "c"]);
// List all entries
let text = "";
for (const entry of letters.entries()) {
  text += entry;
}

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Complete Set Reference Manual

For a complete reference, please visit our:JavaScript Set Reference Manual.

This manual includes descriptions and examples of all Set properties and methods.