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TreeMap

data-structure-typed

data-structure-typed / TreeMap

Class: TreeMap<K, V, R>

Defined in: data-structures/binary-tree/tree-map.ts:26

An ordered Map backed by a red-black tree.

  • Iteration order is ascending by key.
  • No node exposure: all APIs use keys/values only.

Example​

// Set multiple key-value pairs
 const tm = new TreeMap<number, string>();
    tm.setMany([[1, 'a'], [2, 'b'], [3, 'c']]);
    console.log(tm.size); // 3;

Type Parameters​

K​

K = any

V​

V = any

R​

R = [K, V]

Implements​

  • Iterable<[K, V | undefined]>

Constructors​

Constructor​

new TreeMap<K, V, R>(entries?, options?): TreeMap<K, V, R>;

Defined in: data-structures/binary-tree/tree-map.ts:46

Create a TreeMap from an iterable of [key, value] entries or raw elements.

Parameters​

entries?​

| Iterable<[K, V | undefined], any, any> | Iterable<R, any, any>

Iterable of [key, value] tuples, or raw elements if toEntryFn is provided.

options?​

TreeMapOptions<K, V, R> = {}

Configuration options including optional toEntryFn to transform raw elements.

Returns​

TreeMap<K, V, R>

Throws​

If any entry is not a 2-tuple-like value (when no toEntryFn), or when using the default comparator and encountering unsupported/invalid keys (e.g. NaN, invalid Date).

Example​

// Standard usage with entries
const map = new TreeMap([['a', 1], ['b', 2]]);

// Using toEntryFn to transform raw objects
const users = [{ id: 1, name: 'Alice' }, { id: 2, name: 'Bob' }];
const map = new TreeMap<number, User, User>(users, { toEntryFn: u => [u.id, u] });

Accessors​

size​

Get Signature​

get size(): number;

Defined in: data-structures/binary-tree/tree-map.ts:134

Number of entries in the map.

Returns​

number

Methods​

ceiling()​

ceiling(key): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3649

Smallest entry whose key is >= the given key.

Parameters​

key​

K

Returns​

[K, V | undefined] | undefined

Example​

// Event scheduler with time-based lookup
 const events = new TreeMap<Date, string>();

    const meeting = new Date('2024-01-15T10:00:00Z');
    const lunch = new Date('2024-01-15T12:00:00Z');
    const review = new Date('2024-01-15T15:00:00Z');
    const standup = new Date('2024-01-15T09:00:00Z');

    events.set(meeting, 'Team Meeting');
    events.set(lunch, 'Lunch Break');
    events.set(review, 'Code Review');
    events.set(standup, 'Daily Standup');

    // Events are sorted chronologically
    console.log([...events.values()]); // [
 //      'Daily Standup',
 //      'Team Meeting',
 //      'Lunch Break',
 //      'Code Review'
 //    ];

    // Next event after 11:00
    const after11 = new Date('2024-01-15T11:00:00Z');
    console.log(events.ceiling(after11)?.[1]); // 'Lunch Break';

    // Events between 9:30 and 13:00
    const from = new Date('2024-01-15T09:30:00Z');
    const to = new Date('2024-01-15T13:00:00Z');
    const window = events.rangeSearch([from, to]);
    console.log(window.map(([, v]) => v)); // ['Team Meeting', 'Lunch Break'];

clear()​

clear(): void;

Defined in: data-structures/binary-tree/tree-map.ts:1208

Remove all entries.

Returns​

void

Example​

// Remove all
 const tm = new TreeMap<number, string>([[1, 'a']]);
      tm.clear();
      console.log(tm.isEmpty()); // true;

clone()​

clone(): TreeMap<K, V>;

Defined in: data-structures/binary-tree/tree-map.ts:4465

Creates a shallow clone of this map.

Returns​

TreeMap<K, V>

Remarks​

Time O(n log n), Space O(n)

Example​

// Deep clone
 const tm = new TreeMap<number, string>([[1, 'a'], [2, 'b']]);
      const copy = tm.clone();
      copy.delete(1);
      console.log(tm.has(1)); // true;

delete()​

delete(key): boolean;

Defined in: data-structures/binary-tree/tree-map.ts:1041

Delete a key.

Parameters​

key​

K

Returns​

boolean

true if the key existed; otherwise false.

Remarks​

Expected time O(log n)

Example​

// Session management with expiry
 const sessions = new TreeMap<string, number>([
      ['sess_abc', Date.now()],
      ['sess_def', Date.now()],
      ['sess_ghi', Date.now()]
    ]);

    console.log(sessions.size); // 3;
    sessions.delete('sess_def');
    console.log(sessions.has('sess_def')); // false;
    console.log(sessions.size); // 2;

entries()​

entries(): IterableIterator<[K, V | undefined]>;

Defined in: data-structures/binary-tree/tree-map.ts:1710

Iterate over [key, value] entries in ascending key order.

Note: values may be undefined.

Returns​

IterableIterator<[K, V | undefined]>

Example​

// Iterate key-value pairs
 const tm = new TreeMap<number, string>([[3, 'c'], [1, 'a'], [2, 'b']]);
      console.log([...tm.entries()]); // [[1, 'a'], [2, 'b'], [3, 'c']];

every()​

every(callbackfn, thisArg?): boolean;

Defined in: data-structures/binary-tree/tree-map.ts:2567

Test whether all entries satisfy a predicate.

Parameters​

callbackfn​

TreeMapEntryCallback<K, V, boolean, TreeMap<K, V, [K, V]>>

thisArg?​

unknown

Returns​

boolean

Remarks​

Time O(n), Space O(1)

Example​

// Test all entries
 const tm = new TreeMap<number, string>([[1, 'a'], [2, 'b']]);
      console.log(tm.every((v, k) => k > 0)); // true;

filter()​

filter(callbackfn, thisArg?): TreeMap<K, V>;

Defined in: data-structures/binary-tree/tree-map.ts:2228

Create a new TreeMap containing only entries that satisfy the predicate.

Parameters​

callbackfn​

TreeMapEntryCallback<K, V, boolean, TreeMap<K, V, [K, V]>>

thisArg?​

unknown

Returns​

TreeMap<K, V>

Remarks​

Time O(n log n) expected, Space O(n)

Example​

// Filter entries
 const tm = new TreeMap<number, string>([[1, 'a'], [2, 'b'], [3, 'c']]);
      const filtered = tm.filter((v, k) => k > 1);
      console.log([...filtered.keys()]); // [2, 3];

find()​

find(callbackfn, thisArg?): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:2908

Find the first entry that satisfies a predicate.

Parameters​

callbackfn​

TreeMapEntryCallback<K, V, boolean, TreeMap<K, V, [K, V]>>

thisArg?​

unknown

Returns​

[K, V | undefined] | undefined

The first matching [key, value] tuple, or undefined.

Remarks​

Time O(n), Space O(1)

Example​

// Find matching entry
 const tm = new TreeMap<number, string>([[1, 'a'], [2, 'b']]);
      console.log(tm.find(v => v === 'b')?.[0]); // 2;

first()​

first(): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3316

Smallest entry by key.

Returns​

[K, V | undefined] | undefined

Example​

// Leaderboard with ranked scores
 // Use score as key (descending), player name as value
    const leaderboard = new TreeMap<number, string>([], {
      comparator: (a, b) => b - a // descending
    });

    leaderboard.set(1500, 'Alice');
    leaderboard.set(2200, 'Bob');
    leaderboard.set(1800, 'Charlie');
    leaderboard.set(2500, 'Diana');

    // Top 3 players (first 3 in descending order)
    const top3 = [...leaderboard.entries()].slice(0, 3);
    console.log(top3); // [
 //      [2500, 'Diana'],
 //      [2200, 'Bob'],
 //      [1800, 'Charlie']
 //    ];

    // Highest scorer
    console.log(leaderboard.first()); // [2500, 'Diana'];

    // Remove lowest scorer
    console.log(leaderboard.pollLast()); // [1500, 'Alice'];
    console.log(leaderboard.size); // 3;

floor()​

floor(key): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3803

Largest entry whose key is <= the given key.

Parameters​

key​

K

Returns​

[K, V | undefined] | undefined

Example​

// Find the largest key ≤ target
 const versions = new TreeMap<number, string>([
      [1, 'v1.0'],
      [3, 'v3.0'],
      [5, 'v5.0'],
      [7, 'v7.0']
    ]);

    // Largest version ≤ 4
    console.log(versions.floor(4)); // [3, 'v3.0'];
    // Largest version ≤ 5 (exact match)
    console.log(versions.floor(5)); // [5, 'v5.0'];
    // No version ≤ 0
    console.log(versions.floor(0)); // undefined;

forEach()​

forEach(cb, thisArg?): void;

Defined in: data-structures/binary-tree/tree-map.ts:1882

Visit each entry in ascending key order.

Note: callback value may be undefined.

Parameters​

cb​

(value, key, map) => void

thisArg?​

unknown

Returns​

void

Example​

// Execute for each entry
 const tm = new TreeMap<number, string>([[1, 'a'], [2, 'b']]);
      const pairs: string[] = [];
      tm.forEach((v, k) => pairs.push(`${k}:${v}`));
      console.log(pairs); // ['1:a', '2:b'];

get()​

get(key): V | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:672

Get the value under a key.

Parameters​

key​

K

Returns​

V | undefined

Remarks​

Expected time O(log n)

Example​

// Configuration registry with typed lookups
 const config = new TreeMap<string, number>([
      ['maxRetries', 3],
      ['timeout', 5000],
      ['poolSize', 10]
    ]);

    console.log(config.get('timeout')); // 5000;
    console.log(config.get('missing')); // undefined;
    console.log(config.size); // 3;

has()​

has(key): boolean;

Defined in: data-structures/binary-tree/tree-map.ts:855

Test whether a key exists.

Parameters​

key​

K

Returns​

boolean

Remarks​

Expected time O(log n)

Example​

// Feature flag checking
 const flags = new TreeMap<string, boolean>([
      ['darkMode', true],
      ['betaFeature', false],
      ['notifications', true]
    ]);

    console.log(flags.has('darkMode')); // true;
    console.log(flags.has('unknownFlag')); // false;

higher()​

higher(key): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3957

Smallest entry whose key is > the given key.

Parameters​

key​

K

Returns​

[K, V | undefined] | undefined

Example​

// Find the smallest key strictly > target
 const prices = new TreeMap<number, string>([
      [10, 'Basic'],
      [25, 'Standard'],
      [50, 'Premium'],
      [100, 'Enterprise']
    ]);

    // Next tier above $25
    console.log(prices.higher(25)); // [50, 'Premium'];
    // Next tier above $99
    console.log(prices.higher(99)); // [100, 'Enterprise'];
    // Nothing above $100
    console.log(prices.higher(100)); // undefined;

isEmpty()​

isEmpty(): boolean;

Defined in: data-structures/binary-tree/tree-map.ts:297

Whether the map is empty.

Returns​

boolean

Example​

// Check empty
 console.log(new TreeMap().isEmpty()); // true;

keys()​

keys(): IterableIterator<K>;

Defined in: data-structures/binary-tree/tree-map.ts:1372

Iterate over keys in ascending order.

Returns​

IterableIterator<K>

Example​

// Get sorted keys
 const tm = new TreeMap<number, string>([[3, 'c'], [1, 'a']]);
      console.log([...tm.keys()]); // [1, 3];

last()​

last(): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3368

Largest entry by key.

Returns​

[K, V | undefined] | undefined

Example​

// Access the maximum entry
 const scores = new TreeMap<number, string>([
      [85, 'Bob'],
      [92, 'Alice'],
      [78, 'Charlie']
    ]);

    console.log(scores.last()); // [92, 'Alice'];
    console.log(scores.first()); // [78, 'Charlie'];

lower()​

lower(key): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:4109

Largest entry whose key is < the given key.

Parameters​

key​

K

Returns​

[K, V | undefined] | undefined

Example​

// Find the largest key strictly < target
 const temps = new TreeMap<number, string>([
      [0, 'Freezing'],
      [20, 'Cool'],
      [30, 'Warm'],
      [40, 'Hot']
    ]);

    // Largest reading below 30
    console.log(temps.lower(30)); // [20, 'Cool'];
    // Nothing below 0
    console.log(temps.lower(0)); // undefined;

map()​

map<MK, MV>(
   callbackfn, 
   options?, 
thisArg?): TreeMap<MK, MV>;

Defined in: data-structures/binary-tree/tree-map.ts:2050

Create a new TreeMap by mapping each entry to a new [key, value] entry.

This mirrors RedBlackTree.map: mapping produces a new ordered container.

Type Parameters​

MK​

MK

MV​

MV

Parameters​

callbackfn​

TreeMapEntryCallback<K, V, [MK, MV], TreeMap<K, V, [K, V]>>

options?​

Omit<TreeMapOptions<MK, MV, [MK, MV]>, "toEntryFn"> & object = {}

thisArg?​

unknown

Returns​

TreeMap<MK, MV>

Remarks​

Time O(n log n) expected, Space O(n)

Example​

// Transform entries
 const tm = new TreeMap<number, number>([[1, 10], [2, 20]]);
      const doubled = tm.map((v, k) => [k, (v ?? 0) * 2] as [number, number]);
      console.log([...doubled.values()]); // [20, 40];

pollFirst()​

pollFirst(): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3422

Remove and return the smallest entry.

Returns​

[K, V | undefined] | undefined

Example​

// Process items from lowest priority
 const tasks = new TreeMap<number, string>([
      [3, 'Low'],
      [1, 'Critical'],
      [2, 'Medium']
    ]);

    // Process lowest priority first
    console.log(tasks.pollFirst()); // [1, 'Critical'];
    console.log(tasks.pollFirst()); // [2, 'Medium'];
    console.log(tasks.size); // 1;

pollLast()​

pollLast(): [K, V | undefined] | undefined;

Defined in: data-structures/binary-tree/tree-map.ts:3478

Remove and return the largest entry.

Returns​

[K, V | undefined] | undefined

Example​

// Remove the maximum entry
 const bids = new TreeMap<number, string>([
      [100, 'Alice'],
      [150, 'Bob'],
      [120, 'Charlie']
    ]);

    // Remove highest bid
    console.log(bids.pollLast()); // [150, 'Bob'];
    console.log(bids.size); // 2;
    console.log(bids.last()); // [120, 'Charlie'];

print()​

print(): void;

Defined in: data-structures/binary-tree/tree-map.ts:3245

Print a human-friendly representation.

Returns​

void

Remarks​

Time O(n), Space O(n)

Example​

// Display tree
 const tm = new TreeMap<number, string>([[1, 'a']]);
      expect(() => tm.print()).not.toThrow();

rangeSearch()​

rangeSearch(range, options?): [K, V | undefined][];

Defined in: data-structures/binary-tree/tree-map.ts:4281

Return all entries in a given key range.

Parameters​

range​

[K, K]

[low, high]

options?​

TreeMapRangeOptions = {}

Inclusive/exclusive bounds (defaults to inclusive).

Returns​

[K, V | undefined][]

Example​

// Inventory system with price-sorted products
 interface Product {
      name: string;
      price: number;
      stock: number;
    }

    const inventory = new TreeMap<string, Product, Product>(
      [
        { name: 'Widget', price: 9.99, stock: 100 },
        { name: 'Gadget', price: 24.99, stock: 50 },
        { name: 'Doohickey', price: 4.99, stock: 200 }
      ],
      { toEntryFn: p => [p.name, p] }
    );

    // Sorted alphabetically by product name
    console.log([...inventory.keys()]); // ['Doohickey', 'Gadget', 'Widget'];

    // Filter high-stock items
    const highStock = inventory.filter(p => (p?.stock ?? 0) > 75);
    console.log([...highStock.keys()]); // ['Doohickey', 'Widget'];

    // Calculate total inventory value
    const totalValue = inventory.reduce(
      (sum, p) => sum + (p ? p.price * p.stock : 0),
      0
    );
    console.log(totalValue); // toBeCloseTo;

reduce()​

reduce<A>(callbackfn, initialValue): A;

Defined in: data-structures/binary-tree/tree-map.ts:2401

Reduce entries into a single accumulator.

Type Parameters​

A​

A

Parameters​

callbackfn​

TreeMapReduceCallback<K, V, A, TreeMap<K, V, [K, V]>>

initialValue​

A

Returns​

A

Remarks​

Time O(n), Space O(1)

Example​

// Aggregate values
 const tm = new TreeMap<number, number>([[1, 10], [2, 20]]);
      console.log(tm.reduce((acc, v) => acc + (v ?? 0), 0)); // 30;

set()​

set(key, value): this;

Defined in: data-structures/binary-tree/tree-map.ts:487

Set or overwrite a value for a key.

Parameters​

key​

K

value​

V | undefined

Returns​

this

Remarks​

Expected time O(log n)

Example​

// Sorted dictionary for a contact book
 const contacts = new TreeMap<string, string>([
      ['Bob', '555-0102'],
      ['Alice', '555-0101'],
      ['Charlie', '555-0103']
    ]);

    // Contacts are automatically sorted by name
    console.log([...contacts.keys()]); // ['Alice', 'Bob', 'Charlie'];
    console.log(contacts.get('Bob')); // '555-0102';

    // Find the first contact alphabetically after 'B'
    console.log(contacts.ceiling('B')); // ['Bob', '555-0102'];

    // Find contacts in range
    console.log(contacts.rangeSearch(['Alice', 'Bob'])); // [
 //      ['Alice', '555-0101'],
 //      ['Bob', '555-0102']
 //    ];

some()​

some(callbackfn, thisArg?): boolean;

Defined in: data-structures/binary-tree/tree-map.ts:2737

Test whether any entry satisfies a predicate.

Parameters​

callbackfn​

TreeMapEntryCallback<K, V, boolean, TreeMap<K, V, [K, V]>>

thisArg?​

unknown

Returns​

boolean

Remarks​

Time O(n), Space O(1)

Example​

// Test any entry
 const tm = new TreeMap<number, string>([[1, 'a'], [2, 'b']]);
      console.log(tm.some((v, k) => k === 2)); // true;

toArray()​

toArray(): [K, V | undefined][];

Defined in: data-structures/binary-tree/tree-map.ts:3080

Materialize the map into an array of [key, value] tuples.

Returns​

[K, V | undefined][]

Remarks​

Time O(n), Space O(n)

Example​

// Convert to array
 const tm = new TreeMap<number, string>([[2, 'b'], [1, 'a']]);
      console.log(tm.toArray()); // [[1, 'a'], [2, 'b']];

values()​

values(): IterableIterator<V | undefined>;

Defined in: data-structures/binary-tree/tree-map.ts:1544

Iterate over values in ascending key order.

Note: values may be undefined (TreeMap allows storing undefined, like native Map).

Returns​

IterableIterator<V | undefined>

Example​

// Get values in key order
 const tm = new TreeMap<number, string>([[2, 'b'], [1, 'a']]);
      console.log([...tm.values()]); // ['a', 'b'];

createDefaultComparator()​

static createDefaultComparator<K>(): Comparator<K>;

Defined in: data-structures/binary-tree/tree-map.ts:87

Create the strict default comparator.

Supports:

  • number (rejects NaN; treats -0 and 0 as equal)
  • string
  • Date (orders by getTime(), rejects invalid dates)

For other key types, a custom comparator must be provided.

Type Parameters​

K​

K

Returns​

Comparator<K>