data-sampler

"use strict";
/**
 * @file sampler.ts
 * @description Main sampling logic. Routes to the correct strategy implementation
 * based on the configured strategy type. Handles edge cases: empty text,
 * invalid chunkSize, negative overlap.
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.sample = sample;
const length_1 = require("./strategies/length");
const priority_1 = require("./strategies/priority");
const relevance_1 = require("./strategies/relevance");
// ---------------------------------------------------------------------------
// Strategy router
// ---------------------------------------------------------------------------
/**
 * Sample text using the configured strategy.
 *
 * Routing:
 * - "length"   → sampleByLength: fixed-size chunking, document order
 * - "priority" → sampleByPriority: keyword-frequency + position scoring
 * - "relevance" → sampleByRelevance: BM25-style query scoring
 *
 * Edge cases handled:
 * - Empty text → returns empty chunks array
 * - chunkSize < 1 → clamped to 1
 * - Negative overlap → clamped to 0
 * - maxChunks ≤ 0 → treated as unlimited
 *
 * @param text - The input text to sample.
 * @param config - Sampling configuration including strategy selector.
 * @returns A SampleResult with the sampled chunks and metadata.
 */
function sample(text, config) {
    // Normalise config edge cases
    const normalised = {
        ...config,
        chunkSize: config.chunkSize != null ? Math.max(1, config.chunkSize) : undefined,
        overlap: config.overlap != null ? Math.max(0, config.overlap) : undefined,
        maxChunks: config.maxChunks != null && config.maxChunks > 0
            ? config.maxChunks
            : undefined,
    };
    const originalLength = text.length;
    // Empty text edge case
    if (text.length === 0) {
        return {
            chunks: [],
            totalChunks: 0,
            originalLength: 0,
            strategy: config.strategy,
        };
    }
    let chunks;
    switch (config.strategy) {
        case "length": {
            chunks = (0, length_1.sampleByLength)(text, normalised);
            break;
        }
        case "priority": {
            chunks = (0, priority_1.sampleByPriority)(text, normalised);
            break;
        }
        case "relevance": {
            chunks = (0, relevance_1.sampleByRelevance)(text, normalised);
            break;
        }
        default: {
            // Exhaustiveness check: if a new strategy is added to the type but not
            // handled here, TypeScript will flag this line.
            const _exhaustive = config.strategy;
            throw new Error(`Unknown sampling strategy: ${_exhaustive}`);
        }
    }
    return {
        chunks,
        totalChunks: chunks.length,
        originalLength,
        strategy: config.strategy,
    };
}
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