ndx/dist/index.d.ts

Lightweight Full-Text Indexing and Searching Library.

/**
 * Index data structure.
 *
 * @typeparam T Document key.
 */
export interface DocumentIndex<T> {
    /** Additional information about documents. */
    readonly docs: Map<T, DocumentDetails<T>>;
    /** Inverted index root node. */
    readonly root: InvertedIndexNode<T>;
    /** Sum of field lengths in all documents. */
    readonly fSum: Float64Array;
    /** Average of field lengths in all documents. */
    readonly fAvg: Float64Array;
    /** Number of removed documents. */
    removed: number;
    /**
     * Tokenizer is a function that breaks text into words, phrases, symbols, or
     * other meaningful elements called tokens.
     */
    tokenizer(s: string): string[];
    /**
     * Filter is a function that processes tokens and returns terms, terms are
     * used in Inverted Index to index documents.
     */
    filter(s: string): string;
}
/**
 * Inverted Index Node.
 *
 * Inverted index is implemented with a
 * [trie](https://en.wikipedia.org/wiki/Trie) data structure.
 *
 * @typeparam T Document key.
 */
export interface InvertedIndexNode<T> {
    /** Char code key. */
    k: number;
    /** Children nodes. */
    c: InvertedIndexNode<T>[] | null;
    /** Documents associated with this node. */
    d: DocumentPointer<T>[] | null;
}
/**
 * Document Details object stores additional information about documents.
 *
 * @typeparam T Document key.
 */
export interface DocumentDetails<T> {
    /**
     * Document key. It can be a simple unique ID or a direct reference to an
     * original document.
     */
    readonly key: T;
    /**
     * Field count is an array that contains number of terms in each indexed
     * text field.
     */
    readonly fCount: Int32Array;
    /**
     * Removed flag.
     */
    removed: boolean;
}
/**
 * Document pointer contains information about term frequency for a document.
 *
 * @typeparam T Document key.
 */
export interface DocumentPointer<T> {
    /**
     * Reference to a {@link DocumentDetails} object that is used for this
     * document.
     */
    readonly details: DocumentDetails<T>;
    /**
     * Term frequency in each field.
     */
    readonly tf: Int32Array;
}
/**
 * Creates an Index.
 *
 * @typeparam T Document key.
 * @param fieldsNum Number of fields.
 * @returns {@link Index}
 */
export declare const createIndex: <T>(fieldsNum: number, tokenizer: (s: string) => string[], filter: (s: string) => string) => DocumentIndex<T>;
/**
 * Finds inverted index node that matches the `term`.
 *
 * @typeparam T Document key.
 * @param node Root node.
 * @param term Term.
 * @returns Inverted index node that contains `term` or an `undefined` value.
 */
export declare const findInvertedIndexNode: <T>(node: InvertedIndexNode<T> | undefined, term: string) => InvertedIndexNode<T> | undefined;
/**
 * Adds a document to the index.
 *
 * @typeparam T Document key.
 * @typeparam D Document type.
 * @param index {@link DocumentIndex}.
 * @param fieldGetters Field getters.
 * @param key Document key.
 * @param doc Document.
 */
export declare const indexAdd: <T, D>(index: DocumentIndex<T>, fieldGetters: ((doc: D) => string)[], key: T, doc: D) => void;
/**
 * Remove document from the index.
 *
 * @typeparam T Document key.
 * @param index {@link DocumentIndex}.
 * @param key Document key.
 */
export declare const indexRemove: <T>(index: DocumentIndex<T>, key: T) => void;
/**
 * Cleans up removed documents from the {@link DocumentIndex}.
 *
 * @typeparam T Document key.
 * @param index {@link DocumentIndex}.
 */
export declare function indexVacuum<T>(index: DocumentIndex<T>): void;
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