@drip_sync/drip/dist/cea/invert_ppl.js

Scalable incremental sync for MongoDB aggregation pipelines

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.invertPipeline = invertPipeline;
function invertStage(stage) {
    if (stage.type === "match") {
        return {
            type: "match",
            filter: { $nor: [stage.filter] },
        };
    }
    return stage;
}
function invertPipeline(pipeline) {
    const numMatches = pipeline.filter((s) => s.type === "match").length;
    if (numMatches === 0) {
        return [];
    }
    if (numMatches === 1) {
        return [pipeline.map(invertStage)];
    }
    // Inverting a pipeline with multiple $match stages requires
    // it to be split up into multiple pipelines, which we don't
    // bother doing, so we return a single sub-pipeline that
    // matches all.
    return [[]];
}