To filter a map based on keys in JavaScript, you can iterate over the map and add key-value pairs that meet the filter criteria to a new map. This method allows you to create a subset of the original map based on specific key conditions.
We can filter a map based on a range of keys in JavaScript by iterating over the map and adding key-value pairs that fall within the specified range to a new map.
For example,
myMap
with some key-value pairs. In this example, the map has integer keys and string values.filteredMap
to store the filtered key-value pairs.forEach
method and check if each key falls within the specified range.filteredMap
.console.log
function to verify the filtering.const myMap = new Map([
[1, 'one'],
[2, 'two'],
[3, 'three'],
[4, 'four'],
[5, 'five']
]);
// Declare an empty map to store the filtered key-value pairs
const filteredMap = new Map();
// Define the key range
const lowerBound = 2;
const upperBound = 4;
// Iterate over the original map and filter based on the key range
myMap.forEach((value, key) => {
if (key >= lowerBound && key <= upperBound) {
filteredMap.set(key, value);
}
});
// Print the filtered map
console.log('Filtered Map by Key Range:', Array.from(filteredMap));
Filtered Map by Key Range: [[2, 'two'], [3, 'three'], [4, 'four']]
We can filter a map based on specific keys in JavaScript by iterating over the map and adding key-value pairs that match the specified keys to a new map.
For example,
myMap
with some key-value pairs. In this example, the map has integer keys and string values.filteredMap
to store the filtered key-value pairs.forEach
method and check if each key matches one of the specified keys.filteredMap
.console.log
function to verify the filtering.const myMap = new Map([
[1, 'one'],
[2, 'two'],
[3, 'three'],
[4, 'four'],
[5, 'five']
]);
// Declare an empty map to store the filtered key-value pairs
const filteredMap = new Map();
// Define the specific keys to filter by
const keysToFilter = new Set([1, 3, 5]);
// Iterate over the original map and filter based on the specific keys
myMap.forEach((value, key) => {
if (keysToFilter.has(key)) {
filteredMap.set(key, value);
}
});
// Print the filtered map
console.log('Filtered Map by Specific Keys:', Array.from(filteredMap));
Filtered Map by Specific Keys: [[1, 'one'], [3, 'three'], [5, 'five']]
We can filter a map with string keys based on a specific prefix in JavaScript by iterating over the map and adding key-value pairs that have keys starting with the given prefix to a new map.
For example,
myMap
with some key-value pairs. In this example, the map has string keys and string values.filteredMap
to store the filtered key-value pairs.forEach
method and check if each key starts with the specified prefix.filteredMap
.console.log
function to verify the filtering.const myMap = new Map([
['apple', 'fruit'],
['banana', 'fruit'],
['carrot', 'vegetable'],
['apricot', 'fruit'],
['blueberry', 'fruit']
]);
// Declare an empty map to store the filtered key-value pairs
const filteredMap = new Map();
// Define the prefix to filter by
const prefix = 'ap';
// Iterate over the original map and filter based on the prefix
myMap.forEach((value, key) => {
if (key.startsWith(prefix)) {
filteredMap.set(key, value);
}
});
// Print the filtered map
console.log('Filtered Map by Prefix:', Array.from(filteredMap));
Filtered Map by Prefix: [['apple', 'fruit'], ['apricot', 'fruit']]
In this tutorial, we learned How to Filter a Map Based on Keys in JavaScript language with well detailed examples.