JavaScript – Delete a Key from Map

To delete a key from Map in JavaScript, call delete() method on this map and pass the specific key as argument to it.

delete() method returns a boolean value. The return value is true if the key is successfully removed from the map, else, false.

Syntax

The syntax to remove/delete a specific key key from a Map map using delete() method is

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map.delete(key)

Examples

In the following example, we take a Map with keys 'a', 'b', and 'c'. We shall delete the key 'b' using delete() method.

index.html

<!DOCTYPE html>
<html lang="en">
<body>
    <pre id="output"></pre>
    <script>
        var map1 = new Map([
            ['a', 10],
            ['b', 20],
            ['c', 30]
        ]);

        var result = map1.delete('b');

        var displayOutput = 'Is the key removed? ' + result + '\n\n';
        displayOutput += 'Map contents :\n'
        map1.forEach (function(value, key) {
            displayOutput += key + ' - ' + value + '\n';
        });
        document.getElementById('output').innerHTML += displayOutput;

</script>
</body>
</html>

If the specified key is not present, then delete() method does nothing and returns false.

In the following example, we try to delete a key 'x' which is not present in the Map map1.

index.html

<!DOCTYPE html>
<html lang="en">
<body>
    <pre id="output"></pre>
    <script>
        var map1 = new Map([
            ['a', 10],
            ['b', 20],
            ['c', 30]
        ]);

        var result = map1.delete('x');

        var displayOutput = 'Is the key removed? ' + result + '\n\n';
        displayOutput += 'Map contents :\n'
        map1.forEach (function(value, key) {
            displayOutput += key + ' - ' + value + '\n';
        });
        document.getElementById('output').innerHTML += displayOutput;

</script>
</body>
</html>

Conclusion

In this JavaScript Tutorial, we learned how to delete a specific key from a Map in JavaScript using delete() method, with examples.