npm-iswhitetile

iswhitetile

A utility library for chess tile operations. Supports tile color detection, diagonal checks, knight move generation, corner detection, and more.

Installation

npm install iswhitetile

Usage

import { IsWhite, IsBlack, KnightMoves, LegalKnightMoves } from 'iswhitetile';

API

Tiles are represented as standard chess algebraic notation strings (e.g. "a1", "e4"). Files are a–h and ranks are 1–8.

All functions return undefined if given an invalid tile.

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IsValidTile(coor: string): boolean | undefined

Returns true if the coordinate is a valid chess tile.

IsValidTile('e4') // true
IsValidTile('z9') // undefined

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IsWhite(coor: string): boolean | undefined

Returns true if the tile is a white square.

IsWhite('a1') // false
IsWhite('b1') // true

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IsBlack(coor: string): boolean | undefined

Returns true if the tile is a black square.

IsBlack('a1') // true
IsBlack('b1') // false

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IsDiagonal(from: string, to: string): boolean | undefined

Returns true if the two tiles are on the same diagonal.

IsDiagonal('a1', 'h8') // true
IsDiagonal('a1', 'a8') // false

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IsCorner(coor: string): boolean | undefined

Returns true if the tile is one of the four corner squares (a1, a8, h1, h8).

IsCorner('a1') // true
IsCorner('e4') // false

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LegalKnightMoves(coor: string): string[] | undefined

Returns an array of valid destination tiles a knight can legally move to from the given tile.

LegalKnightMoves('a1') // ['b3', 'c2']
LegalKnightMoves('e4') // ['d6', 'f6', 'c5', 'g5', 'c3', 'g3', 'd2', 'f2']

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NumberOfLegalKnightMoves(coor: string): number | undefined

Returns the count of legal knight moves from the given tile.

NumberOfLegalKnightMoves('a1') // 2
NumberOfLegalKnightMoves('e4') // 8

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KnightMoves(dx: number, dy: number): [number, number][]

Returns all 8 relative knight move offsets for the given step sizes.

KnightMoves(2, 1)
// [[2,1],[2,-1],[-2,1],[-2,-1],[1,2],[1,-2],[-1,2],[-1,-2]]

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knightMovesGrid

A pre-computed 8×8 grid where each cell contains the number of legal knight moves from that square.

import { knightMovesGrid } from 'iswhitetile';
// knightMovesGrid[0][0] === 2  (a1)
// knightMovesGrid[3][3] === 8  (d4)

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toIndex(coor: string): [number, number] | undefined

Converts a tile string to a [fileIndex, rankIndex] tuple (0-based).

toIndex('a1') // [0, 0]
toIndex('h8') // [7, 7]

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toCharCode(coor: string): [number, number] | undefined

Converts a tile string to a [fileCharCode, rankCharCode] tuple.

toCharCode('a1') // [97, 49]

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validateCoor: RegExp

A regular expression that matches valid chess tile coordinates.

validateCoor.test('e4') // true
validateCoor.test('z9') // false

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RandomTile(): string

Returns a random valid chess tile.

RandomTile() // e.g. 'f3'

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RandomTiles(length: number): string[]

Returns an array of length random valid chess tiles.

RandomTiles(3) // e.g. ['a2', 'h7', 'c5']

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License

MIT