read json lines field values

packages/api/src/controllers/jsldata.js

@@ -1,3 +1,4 @@
+const { filterName } = require('dbgate-tools');
 const fs = require('fs');
 const lineReader = require('line-reader');
 const _ = require('lodash');
@@ -148,6 +149,19 @@ module.exports = {
     return {};
   },
 
+  loadFieldValues_meta: true,
+  async loadFieldValues({ jslid, field, search }) {
+    const datastore = await this.ensureDatastore(jslid);
+    const res = new Set();
+    await datastore.enumRows(row => {
+      if (!filterName(search, row[field])) return true;
+      res.add(row[field]);
+      return res.size < 100;
+    });
+    // @ts-ignore
+    return [...res].map(value => ({ value }));
+  },
+
   async notifyChangedStats(stats) {
     // console.log('SENDING STATS', JSON.stringify(stats));
     const datastore = this.datastores[stats.jslid];

packages/api/src/utility/JsonLinesDatastore.js

@@ -159,6 +159,18 @@ class JsonLinesDatastore {
     }
   }
 
+  async enumRows(eachRow) {
+    await lock.acquire('reader', async () => {
+      await this._ensureReader(0, null);
+      for (;;) {
+        const line = await this._readLine(true);
+        if (line == null) break;
+        const shouldContinue = eachRow(line);
+        if (!shouldContinue) break;
+      }
+    });
+  }
+
   async getRows(offset, limit, filter) {
     const res = [];
     await lock.acquire('reader', async () => {